Apply r316339 to vendor area.

38 files changed, 1083 insertions, 1683 deletions

diff --git a/brac.c b/brac.c
index 10a0843caa69..298a313126eb 100644
--- a/brac.c
+++ b/brac.c
@@ -24,18 +24,14 @@
  * "close bracket" are given.
  */
 	public void
-match_brac(obrac, cbrac, forwdir, n)
-	register int obrac;
-	register int cbrac;
-	int forwdir;
-	int n;
+match_brac(int obrac, int cbrac, int forwdir, int n)
 {
-	register int c;
-	register int nest;
+	int c;
+	int nest;
 	POSITION pos;
-	int (*chget)();
+	int (*chget)(void);
 
-	extern int ch_forw_get(), ch_back_get();
+	extern int ch_forw_get(void), ch_back_get(void);
 
 	/*
 	 * Seek to the line containing the open bracket.
diff --git a/ch.c b/ch.c
index da729c5dec06..bffd75ee8c84 100644
--- a/ch.c
+++ b/ch.c
@@ -144,13 +144,13 @@ static int ch_addbuf();
  * Get the character pointed to by the read pointer.
  */
 	int
-ch_get()
+ch_get(void)
 {
-	register struct buf *bp;
-	register struct bufnode *bn;
-	register int n;
-	register int slept;
-	register int h;
+	struct buf *bp;
+	struct bufnode *bn;
+	int n;
+	int slept;
+	int h;
 	POSITION pos;
 	POSITION len;
 
@@ -378,8 +378,7 @@ ch_get()
  * a single char onto an input file descriptor.
  */
 	public void
-ch_ungetchar(c)
-	int c;
+ch_ungetchar(int c)
 {
 	if (c != -1 && ch_ungotchar != -1)
 		error("ch_ungetchar overrun", NULL_PARG);
@@ -392,7 +391,7 @@ ch_ungetchar(c)
  * If we haven't read all of standard input into it, do that now.
  */
 	public void
-end_logfile()
+end_logfile(void)
 {
 	static int tried = FALSE;
 
@@ -417,10 +416,10 @@ end_logfile()
  * Write all the existing buffered data to the log file.
  */
 	public void
-sync_logfile()
+sync_logfile(void)
 {
-	register struct buf *bp;
-	register struct bufnode *bn;
+	struct buf *bp;
+	struct bufnode *bn;
 	int warned = FALSE;
 	BLOCKNUM block;
 	BLOCKNUM nblocks;
@@ -454,12 +453,11 @@ sync_logfile()
  * Determine if a specific block is currently in one of the buffers.
  */
 	static int
-buffered(block)
-	BLOCKNUM block;
+buffered(BLOCKNUM block)
 {
-	register struct buf *bp;
-	register struct bufnode *bn;
-	register int h;
+	struct buf *bp;
+	struct bufnode *bn;
+	int h;
 
 	h = BUFHASH(block);
 	FOR_BUFS_IN_CHAIN(h, bn)
@@ -476,8 +474,7 @@ buffered(block)
  * Return 0 if successful, non-zero if can't seek there.
  */
 	public int
-ch_seek(pos)
-	register POSITION pos;
+ch_seek(POSITION pos)
 {
 	BLOCKNUM new_block;
 	POSITION len;
@@ -515,7 +512,7 @@ ch_seek(pos)
  * Seek to the end of the file.
  */
 	public int
-ch_end_seek()
+ch_end_seek(void)
 {
 	POSITION len;
 
@@ -542,10 +539,10 @@ ch_end_seek()
  * Seek to the last position in the file that is currently buffered.
  */
 	public int
-ch_end_buffer_seek()
+ch_end_buffer_seek(void)
 {
-	register struct buf *bp;
-	register struct bufnode *bn;
+	struct buf *bp;
+	struct bufnode *bn;
 	POSITION buf_pos;
 	POSITION end_pos;
 
@@ -570,10 +567,10 @@ ch_end_buffer_seek()
  * beginning of the pipe is no longer buffered.
  */
 	public int
-ch_beg_seek()
+ch_beg_seek(void)
 {
-	register struct bufnode *bn;
-	register struct bufnode *firstbn;
+	struct bufnode *bn;
+	struct bufnode *firstbn;
 
 	/*
 	 * Try a plain ch_seek first.
@@ -602,7 +599,7 @@ ch_beg_seek()
  * Return the length of the file, if known.
  */
 	public POSITION
-ch_length()
+ch_length(void)
 {
 	if (thisfile == NULL)
 		return (NULL_POSITION);
@@ -619,7 +616,7 @@ ch_length()
  * Return the current position in the file.
  */
 	public POSITION
-ch_tell()
+ch_tell(void)
 {
 	if (thisfile == NULL)
 		return (NULL_POSITION);
@@ -630,9 +627,9 @@ ch_tell()
  * Get the current char and post-increment the read pointer.
  */
 	public int
-ch_forw_get()
+ch_forw_get(void)
 {
-	register int c;
+	int c;
 
 	if (thisfile == NULL)
 		return (EOI);
@@ -653,7 +650,7 @@ ch_forw_get()
  * Pre-decrement the read pointer and get the new current char.
  */
 	public int
-ch_back_get()
+ch_back_get(void)
 {
 	if (thisfile == NULL)
 		return (EOI);
@@ -676,8 +673,7 @@ ch_back_get()
  * bufspace is in units of 1024 bytes.  -1 mean no limit.
  */
 	public void
-ch_setbufspace(bufspace)
-	int bufspace;
+ch_setbufspace(int bufspace)
 {
 	if (bufspace < 0)
 		maxbufs = -1;
@@ -693,9 +689,9 @@ ch_setbufspace(bufspace)
  * Flush (discard) any saved file state, including buffer contents.
  */
 	public void
-ch_flush()
+ch_flush(void)
 {
-	register struct bufnode *bn;
+	struct bufnode *bn;
 
 	if (thisfile == NULL)
 		return;
@@ -760,10 +756,10 @@ ch_flush()
  * The buffer is added to the tail of the buffer chain.
  */
 	static int
-ch_addbuf()
+ch_addbuf(void)
 {
-	register struct buf *bp;
-	register struct bufnode *bn;
+	struct buf *bp;
+	struct bufnode *bn;
 
 	/*
 	 * Allocate and initialize a new buffer and link it 
@@ -785,9 +781,9 @@ ch_addbuf()
  *
  */
 	static void
-init_hashtbl()
+init_hashtbl(void)
 {
-	register int h;
+	int h;
 
 	for (h = 0;  h < BUFHASH_SIZE;  h++)
 	{
@@ -800,9 +796,9 @@ init_hashtbl()
  * Delete all buffers for this file.
  */
 	static void
-ch_delbufs()
+ch_delbufs(void)
 {
-	register struct bufnode *bn;
+	struct bufnode *bn;
 
 	while (ch_bufhead != END_OF_CHAIN)
 	{
@@ -818,8 +814,7 @@ ch_delbufs()
  * Is it possible to seek on a file descriptor?
  */
 	public int
-seekable(f)
-	int f;
+seekable(int f)
 {
 #if MSDOS_COMPILER
 	extern int fd0;
@@ -840,7 +835,7 @@ seekable(f)
  * This is used after an ignore_eof read, during which the EOF may change.
  */
 	public void
-ch_set_eof()
+ch_set_eof(void)
 {
 	ch_fsize = ch_fpos;
 }
@@ -850,9 +845,7 @@ ch_set_eof()
  * Initialize file state for a new file.
  */
 	public void
-ch_init(f, flags)
-	int f;
-	int flags;
+ch_init(int f, int flags)
 {
 	/*
 	 * See if we already have a filestate for this file.
@@ -891,7 +884,7 @@ ch_init(f, flags)
  * Close a filestate.
  */
 	public void
-ch_close()
+ch_close(void)
 {
 	int keepstate = FALSE;
 
@@ -934,7 +927,7 @@ ch_close()
  * Return ch_flags for the current file.
  */
 	public int
-ch_getflags()
+ch_getflags(void)
 {
 	if (thisfile == NULL)
 		return (0);
diff --git a/charset.c b/charset.c
index 4c62664e73d1..db7e848f0c87 100644
--- a/charset.c
+++ b/charset.c
@@ -130,12 +130,11 @@ public int binattr = AT_STANDOUT;
  *	c control character
  */
 	static void
-ichardef(s)
-	char *s;
+ichardef(char *s)
 {
-	register char *cp;
-	register int n;
-	register char v;
+	char *cp;
+	int n;
+	char v;
 
 	n = 0;
 	v = 0;
@@ -187,12 +186,10 @@ ichardef(s)
  * The valid charset names are listed in the "charsets" array.
  */
 	static int
-icharset(name, no_error)
-	register char *name;
-	int no_error;
+icharset(char *name, int no_error)
 {
-	register struct charset *p;
-	register struct cs_alias *a;
+	struct charset *p;
+	struct cs_alias *a;
 
 	if (name == NULL || *name == '\0')
 		return (0);
@@ -230,9 +227,9 @@ icharset(name, no_error)
  * Define a charset, given a locale name.
  */
 	static void
-ilocale()
+ilocale(void)
 {
-	register int c;
+	int c;
 
 	for (c = 0;  c < (int) sizeof(chardef);  c++)
 	{
@@ -250,10 +247,7 @@ ilocale()
  * Define the printing format for control (or binary utf) chars.
  */
    	static void
-setbinfmt(s, fmtvarptr, default_fmt)
-	char *s;
-	char **fmtvarptr;
-	char *default_fmt;
+setbinfmt(char *s, char **fmtvarptr, char *default_fmt)
 {
 	if (s && utf_mode)
 	{
@@ -299,7 +293,7 @@ setbinfmt(s, fmtvarptr, default_fmt)
  *
  */
 	static void
-set_charset()
+set_charset(void)
 {
 	char *s;
 
@@ -370,7 +364,7 @@ set_charset()
  * Initialize charset data structures.
  */
 	public void
-init_charset()
+init_charset(void)
 {
 	char *s;
 
@@ -391,8 +385,7 @@ init_charset()
  * Is a given character a "binary" character?
  */
 	public int
-binary_char(c)
-	LWCHAR c;
+binary_char(LWCHAR c)
 {
 	if (utf_mode)
 		return (is_ubin_char(c));
@@ -404,8 +397,7 @@ binary_char(c)
  * Is a given character a "control" character?
  */
 	public int
-control_char(c)
-	LWCHAR c;
+control_char(LWCHAR c)
 {
 	c &= 0377;
 	return (chardef[c] & IS_CONTROL_CHAR);
@@ -416,8 +408,7 @@ control_char(c)
  * For example, in the "ascii" charset '\3' is printed as "^C".
  */
 	public char *
-prchar(c)
-	LWCHAR c;
+prchar(LWCHAR c)
 {
 	/* {{ This buffer can be overrun if LESSBINFMT is a long string. }} */
 	static char buf[32];
@@ -452,8 +443,7 @@ prchar(c)
  * Return the printable form of a UTF-8 character.
  */
 	public char *
-prutfchar(ch)
-	LWCHAR ch;
+prutfchar(LWCHAR ch)
 {
 	static char buf[32];
 
@@ -483,8 +473,7 @@ prutfchar(ch)
  * Get the length of a UTF-8 character in bytes.
  */
 	public int
-utf_len(ch)
-	char ch;
+utf_len(char ch)
 {
 	if ((ch & 0x80) == 0)
 		return 1;
@@ -506,9 +495,7 @@ utf_len(ch)
  * Does the parameter point to the lead byte of a well-formed UTF-8 character?
  */
 	public int
-is_utf8_well_formed(s, slen)
-	unsigned char *s;
-	int slen;
+is_utf8_well_formed(unsigned char *s, int slen)
 {
 	int i;
 	int len;
@@ -543,9 +530,7 @@ is_utf8_well_formed(s, slen)
  * Return number of invalid UTF-8 sequences found in a buffer.
  */
 	public int
-utf_bin_count(data, len)
-	unsigned char *data;
-	int len;
+utf_bin_count(unsigned char *data, int len)
 {
 	int bin_count = 0;
 	while (len > 0)
@@ -572,8 +557,7 @@ utf_bin_count(data, len)
  * Get the value of a UTF-8 character.
  */
 	public LWCHAR
-get_wchar(p)
-	char *p;
+get_wchar(constant char *p)
 {
 	switch (utf_len(p[0]))
 	{
@@ -624,9 +608,7 @@ get_wchar(p)
  * Store a character into a UTF-8 string.
  */
 	public void
-put_wchar(pp, ch)
-	char **pp;
-	LWCHAR ch;
+put_wchar(char **pp, LWCHAR ch)
 {
 	if (!utf_mode || ch < 0x80) 
 	{
@@ -674,14 +656,11 @@ put_wchar(pp, ch)
  * Step forward or backward one character in a string.
  */
 	public LWCHAR
-step_char(pp, dir, limit)
-	char **pp;
-	signed int dir;
-	char *limit;
+step_char(constant char **pp, signed int dir, constant char *limit)
 {
 	LWCHAR ch;
 	int len;
-	char *p = *pp;
+	constant char *p = *pp;
 
 	if (!utf_mode)
 	{
@@ -744,9 +723,7 @@ static struct wchar_range comb_table[] = {
 
 
 	static int
-is_in_table(ch, table)
-	LWCHAR ch;
-	struct wchar_range_table *table;
+is_in_table(LWCHAR ch, struct wchar_range_table *table)
 {
 	int hi;
 	int lo;
@@ -774,8 +751,7 @@ is_in_table(ch, table)
  * If a composing character follows any char, the two combine into one glyph.
  */
 	public int
-is_composing_char(ch)
-	LWCHAR ch;
+is_composing_char(LWCHAR ch)
 {
 	return is_in_table(ch, &compose_table);
 }
@@ -784,8 +760,7 @@ is_composing_char(ch)
  * Should this UTF-8 character be treated as binary?
  */
 	public int
-is_ubin_char(ch)
-	LWCHAR ch;
+is_ubin_char(LWCHAR ch)
 {
 	return is_in_table(ch, &ubin_table);
 }
@@ -794,8 +769,7 @@ is_ubin_char(ch)
  * Is this a double width UTF-8 character?
  */
 	public int
-is_wide_char(ch)
-	LWCHAR ch;
+is_wide_char(LWCHAR ch)
 {
 	return is_in_table(ch, &wide_table);
 }
@@ -806,9 +780,7 @@ is_wide_char(ch)
  * a specific char (not any char), the two combine into one glyph.
  */
 	public int
-is_combining_char(ch1, ch2)
-	LWCHAR ch1;
-	LWCHAR ch2;
+is_combining_char(LWCHAR ch1, LWCHAR ch2)
 {
 	/* The table is small; use linear search. */
 	int i;
diff --git a/cmdbuf.c b/cmdbuf.c
index 69d7414e9734..9631e18daafe 100644
--- a/cmdbuf.c
+++ b/cmdbuf.c
@@ -32,7 +32,7 @@ static int literal;		/* Next input char should not be interpreted */
 static int updown_match = -1;	/* Prefix length in up/down movement */
 
 #if TAB_COMPLETE_FILENAME
-static int cmd_complete();
+static int cmd_complete(int action);
 /*
  * These variables are statics used by cmd_complete.
  */
@@ -114,7 +114,7 @@ static int cmd_mbc_buf_index;
  * Reset command buffer (to empty).
  */
 	public void
-cmd_reset()
+cmd_reset(void)
 {
 	cp = cmdbuf;
 	*cp = '\0';
@@ -129,7 +129,7 @@ cmd_reset()
  * Clear command line.
  */
 	public void
-clear_cmd()
+clear_cmd(void)
 {
 	cmd_col = prompt_col = 0;
 	cmd_mbc_buf_len = 0;
@@ -140,15 +140,14 @@ clear_cmd()
  * Display a string, usually as a prompt for input into the command buffer.
  */
 	public void
-cmd_putstr(s)
-	char *s;
+cmd_putstr(constant char *s)
 {
 	LWCHAR prev_ch = 0;
 	LWCHAR ch;
-	char *endline = s + strlen(s);
+	constant char *endline = s + strlen(s);
 	while (*s != '\0')
 	{
-		char *ns = s;
+		constant char *ns = s;
 		ch = step_char(&ns, +1, endline);
 		while (s < ns)
 			putchr(*s++);
@@ -171,10 +170,10 @@ cmd_putstr(s)
  * How many characters are in the command buffer?
  */
 	public int
-len_cmdbuf()
+len_cmdbuf(void)
 {
-	char *s = cmdbuf;
-	char *endline = s + strlen(s);
+	constant char *s = cmdbuf;
+	constant char *endline = s + strlen(s);
 	int len = 0;
 
 	while (*s != '\0')
@@ -189,12 +188,7 @@ len_cmdbuf()
  * Common part of cmd_step_right() and cmd_step_left().
  */
 	static char *
-cmd_step_common(p, ch, len, pwidth, bswidth)
-	char *p;
-	LWCHAR ch;
-	int len;
-	int *pwidth;
-	int *bswidth;
+cmd_step_common(constant char *p, LWCHAR ch, int len, int *pwidth, int *bswidth)
 {
 	char *pr;
 
@@ -256,13 +250,10 @@ cmd_step_common(p, ch, len, pwidth, bswidth)
  * Step a pointer one character right in the command buffer.
  */
 	static char *
-cmd_step_right(pp, pwidth, bswidth)
-	char **pp;
-	int *pwidth;
-	int *bswidth;
+cmd_step_right(char **pp, int *pwidth, int *bswidth)
 {
 	char *p = *pp;
-	LWCHAR ch = step_char(pp, +1, p + strlen(p));
+	LWCHAR ch = step_char((constant char **)pp, +1, p + strlen(p));
 
 	return cmd_step_common(p, ch, *pp - p, pwidth, bswidth);
 }
@@ -271,13 +262,10 @@ cmd_step_right(pp, pwidth, bswidth)
  * Step a pointer one character left in the command buffer.
  */
 	static char *
-cmd_step_left(pp, pwidth, bswidth)
-	char **pp;
-	int *pwidth;
-	int *bswidth;
+cmd_step_left(char **pp, int *pwidth, int *bswidth)
 {
 	char *p = *pp;
-	LWCHAR ch = step_char(pp, -1, cmdbuf);
+	LWCHAR ch = step_char((constant char **)pp, -1, cmdbuf);
 
 	return cmd_step_common(*pp, ch, p - *pp, pwidth, bswidth);
 }
@@ -287,8 +275,7 @@ cmd_step_left(pp, pwidth, bswidth)
  * Then position the cursor just after the char old_cp (a pointer into cmdbuf).
  */
 	static void
-cmd_repaint(old_cp)
-	char *old_cp;
+cmd_repaint(char *old_cp)
 {
 	/*
 	 * Repaint the line from the current position.
@@ -298,7 +285,7 @@ cmd_repaint(old_cp)
 	{
 		char *np = cp;
 		int width;
-		char *pr = cmd_step_right(&np, &width, NULL);
+		constant char *pr = cmd_step_right(&np, &width, NULL);
 		if (cmd_col + width >= sc_width)
 			break;
 		cp = np;
@@ -328,7 +315,7 @@ cmd_repaint(old_cp)
  * and set cp to the corresponding char in cmdbuf.
  */
 	static void
-cmd_home()
+cmd_home(void)
 {
 	while (cmd_col > prompt_col)
 	{
@@ -347,7 +334,7 @@ cmd_home()
  * Shift the cmdbuf display left a half-screen.
  */
 	static void
-cmd_lshift()
+cmd_lshift(void)
 {
 	char *s;
 	char *save_cp;
@@ -385,7 +372,7 @@ cmd_lshift()
  * Shift the cmdbuf display right a half-screen.
  */
 	static void
-cmd_rshift()
+cmd_rshift(void)
 {
 	char *s;
 	char *save_cp;
@@ -415,7 +402,7 @@ cmd_rshift()
  * Move cursor right one character.
  */
 	static int
-cmd_right()
+cmd_right(void)
 {
 	char *pr;
 	char *ncp;
@@ -450,7 +437,7 @@ cmd_right()
  * Move cursor left one character.
  */
 	static int
-cmd_left()
+cmd_left(void)
 {
 	char *ncp;
 	int width, bswidth;
@@ -480,9 +467,7 @@ cmd_left()
  * Insert a char into the command buffer, at the current position.
  */
 	static int
-cmd_ichar(cs, clen)
-	char *cs;
-	int clen;
+cmd_ichar(char *cs, int clen)
 {
 	char *s;
 	
@@ -517,9 +502,9 @@ cmd_ichar(cs, clen)
  * Delete the char to the left of the cursor.
  */
 	static int
-cmd_erase()
+cmd_erase(void)
 {
-	register char *s;
+	char *s;
 	int clen;
 
 	if (cp == cmdbuf)
@@ -566,7 +551,7 @@ cmd_erase()
  * Delete the char under the cursor.
  */
 	static int
-cmd_delete()
+cmd_delete(void)
 {
 	if (*cp == '\0')
 	{
@@ -585,7 +570,7 @@ cmd_delete()
  * Delete the "word" to the left of the cursor.
  */
 	static int
-cmd_werase()
+cmd_werase(void)
 {
 	if (cp > cmdbuf && cp[-1] == ' ')
 	{
@@ -611,7 +596,7 @@ cmd_werase()
  * Delete the "word" under the cursor.
  */
 	static int
-cmd_wdelete()
+cmd_wdelete(void)
 {
 	if (*cp == ' ')
 	{
@@ -637,7 +622,7 @@ cmd_wdelete()
  * Delete all chars in the command buffer.
  */
 	static int
-cmd_kill()
+cmd_kill(void)
 {
 	if (cmdbuf[0] == '\0')
 	{
@@ -663,9 +648,7 @@ cmd_kill()
  * Select an mlist structure to be the current command history.
  */
 	public void
-set_mlist(mlist, cmdflags)
-	void *mlist;
-	int cmdflags;
+set_mlist(constant void *mlist, int cmdflags)
 {
 #if CMD_HISTORY
 	curr_mlist = (struct mlist *) mlist;
@@ -684,8 +667,7 @@ set_mlist(mlist, cmdflags)
  * cmdbuf's corresponding chars.
  */
 	static int
-cmd_updown(action)
-	int action;
+cmd_updown(int action)
 {
 	char *s;
 	struct mlist *ml;
@@ -747,10 +729,7 @@ cmd_updown(action)
  * Add a string to an mlist.
  */
 	public void
-cmd_addhist(mlist, cmd, modified)
-	struct mlist *mlist;
-	char *cmd;
-	int modified;
+cmd_addhist(struct mlist *constant mlist, char *cmd, int modified)
 {
 #if CMD_HISTORY
 	struct mlist *ml;
@@ -793,7 +772,7 @@ cmd_addhist(mlist, cmd, modified)
  * Add it to the currently selected history list.
  */
 	public void
-cmd_accept()
+cmd_accept(void)
 {
 #if CMD_HISTORY
 	/*
@@ -815,8 +794,7 @@ cmd_accept()
  *	CC_QUIT	The char requests the current command to be aborted.
  */
 	static int
-cmd_edit(c)
-	int c;
+cmd_edit(int c)
 {
 	int action;
 	int flags;
@@ -931,8 +909,7 @@ cmd_edit(c)
  * Insert a string into the command buffer, at the current position.
  */
 	static int
-cmd_istr(str)
-	char *str;
+cmd_istr(char *str)
 {
 	char *s;
 	int action;
@@ -941,7 +918,7 @@ cmd_istr(str)
 	for (s = str;  *s != '\0';  )
 	{
 		char *os = s;
-		step_char(&s, +1, endline);
+		step_char((constant char **)&s, +1, endline);
 		action = cmd_ichar(os, s - os);
 		if (action != CC_OK)
 		{
@@ -959,7 +936,7 @@ cmd_istr(str)
  * cursor at the end of the word.
  */
 	static char *
-delimit_word()
+delimit_word(void)
 {
 	char *word;
 #if SPACES_IN_FILENAMES
@@ -1046,7 +1023,7 @@ delimit_word()
  * which start with that word, and set tk_text to that list.
  */
 	static void
-init_compl()
+init_compl(void)
 {
 	char *word;
 	char c;
@@ -1109,9 +1086,7 @@ init_compl()
  * Return the next word in the current completion list.
  */
 	static char *
-next_compl(action, prev)
-	int action;
-	char *prev;
+next_compl(int action, char *prev)
 {
 	switch (action)
 	{
@@ -1131,8 +1106,7 @@ next_compl(action, prev)
  * or a subsequent time (step thru the list).
  */
 	static int
-cmd_complete(action)
-	int action;
+cmd_complete(int action)
 {
 	char *s;
 
@@ -1229,8 +1203,7 @@ fail:
  *	CC_ERROR	The char could not be accepted due to an error.
  */
 	public int
-cmd_char(c)
-	int c;
+cmd_char(int c)
 {
 	int action;
 	int len;
@@ -1319,8 +1292,7 @@ cmd_char(c)
  * Return the number currently in the command buffer.
  */
 	public LINENUM
-cmd_int(frac)
-	long *frac;
+cmd_int(long *frac)
 {
 	char *p;
 	LINENUM n = 0;
@@ -1341,7 +1313,7 @@ cmd_int(frac)
  * Return a pointer to the command buffer.
  */
 	public char *
-get_cmdbuf()
+get_cmdbuf(void)
 {
 	return (cmdbuf);
 }
@@ -1351,7 +1323,7 @@ get_cmdbuf()
  * Return the last (most recent) string in the current command history.
  */
 	public char *
-cmd_lastpattern()
+cmd_lastpattern(void)
 {
 	if (curr_mlist == NULL)
 		return (NULL);
@@ -1363,8 +1335,7 @@ cmd_lastpattern()
 /*
  */
 	static int
-mlist_size(ml)
-	struct mlist *ml;
+mlist_size(struct mlist *ml)
 {
 	int size = 0;
 	for (ml = ml->next;  ml->string != NULL;  ml = ml->next)
@@ -1376,7 +1347,7 @@ mlist_size(ml)
  * Get the name of the history file.
  */
 	static char *
-histfile_name()
+histfile_name(void)
 {
 	char *home;
 	char *name;
@@ -1416,11 +1387,8 @@ histfile_name()
  * Read a .lesshst file and call a callback for each line in the file.
  */
 	static void
-read_cmdhist2(action, uparam, skip_search, skip_shell)
-	void (*action)(void*,struct mlist*,char*);
-	void *uparam;
-	int skip_search;
-	int skip_shell;
+read_cmdhist2(void (*action)(void*,struct mlist*,char*), void *uparam,
+    int skip_search, int skip_shell)
 {
 	struct mlist *ml = NULL;
 	char line[CMDBUF_SIZE];
@@ -1480,11 +1448,8 @@ read_cmdhist2(action, uparam, skip_search, skip_shell)
 }
 
 	static void
-read_cmdhist(action, uparam, skip_search, skip_shell)
-	void (*action)(void*,struct mlist*,char*);
-	void *uparam;
-	int skip_search;
-	int skip_shell;
+read_cmdhist(void (*action)(void*,struct mlist*,char*), void *uparam,
+    int skip_search, int skip_shell)
 {
 	read_cmdhist2(action, uparam, skip_search, skip_shell);
 	(*action)(uparam, NULL, NULL); /* signal end of file */
@@ -1503,7 +1468,7 @@ addhist_init(void *uparam, struct mlist *ml, char *string)
  * Initialize history from a .lesshist file.
  */
 	public void
-init_cmdhist()
+init_cmdhist(void)
 {
 #if CMD_HISTORY
 	read_cmdhist(&addhist_init, NULL, 0, 0);
@@ -1515,9 +1480,7 @@ init_cmdhist()
  */
 #if CMD_HISTORY
 	static void
-write_mlist_header(ml, f)
-	struct mlist *ml;
-	FILE *f;
+write_mlist_header(struct mlist *ml, FILE *f)
 {
 	if (ml == &mlist_search)
 		fprintf(f, "%s\n", HISTFILE_SEARCH_SECTION);
@@ -1531,9 +1494,7 @@ write_mlist_header(ml, f)
  * Write all modified entries in an mlist to the history file.
  */
 	static void
-write_mlist(ml, f)
-	struct mlist *ml;
-	FILE *f;
+write_mlist(struct mlist *ml, FILE *f)
 {
 	for (ml = ml->next;  ml->string != NULL;  ml = ml->next)
 	{
@@ -1549,8 +1510,7 @@ write_mlist(ml, f)
  * Make a temp name in the same directory as filename.
  */
 	static char *
-make_tempname(filename)
-	char *filename;
+make_tempname(char *filename)
 {
 	char lastch;
 	char *tempname = ecalloc(1, strlen(filename)+1);
@@ -1613,8 +1573,7 @@ copy_hist(void *uparam, struct mlist *ml, char *string)
  * Make a file readable only by its owner.
  */
 	static void
-make_file_private(f)
-	FILE *f;
+make_file_private(FILE *f)
 {
 #if HAVE_FCHMOD
 	int do_chmod = 1;
@@ -1634,7 +1593,7 @@ make_file_private(f)
  * Does the history file need to be updated?
  */
 	static int
-histfile_modified()
+histfile_modified(void)
 {
 	if (mlist_search.modified)
 		return 1;
@@ -1649,7 +1608,7 @@ histfile_modified()
  * Update the .lesshst file.
  */
 	public void
-save_cmdhist()
+save_cmdhist(void)
 {
 #if CMD_HISTORY
 	char *histname;
diff --git a/command.c b/command.c
index c31fa81a3218..34f636af4d0a 100644
--- a/command.c
+++ b/command.c
@@ -82,7 +82,7 @@ struct ungot {
 };
 static struct ungot* ungot = NULL;
 
-static void multi_search();
+static void multi_search(char *pattern, int n, int silent);
 
 /*
  * Move the cursor to start of prompt line before executing a command.
@@ -90,7 +90,7 @@ static void multi_search();
  * updating the screen.
  */
 	static void
-cmd_exec()
+cmd_exec(void)
 {
 #if HILITE_SEARCH
 	clear_attn();
@@ -103,11 +103,7 @@ cmd_exec()
  * Set up the display to start a new multi-character command.
  */
 	static void
-start_mca(action, prompt, mlist, cmdflags)
-	int action;
-	constant char *prompt;
-	constant void *mlist;
-	int cmdflags;
+start_mca(int action, constant char *prompt, constant void *mlist, int cmdflags)
 {
 	mca = action;
 	clear_bot();
@@ -117,7 +113,7 @@ start_mca(action, prompt, mlist, cmdflags)
 }
 
 	public int
-in_mca()
+in_mca(void)
 {
 	return (mca != 0 && mca != A_PREFIX);
 }
@@ -126,7 +122,7 @@ in_mca()
  * Set up the display to start a new search command.
  */
 	static void
-mca_search()
+mca_search(void)
 {
 #if HILITE_SEARCH
 	if (search_type & SRCH_FILTER)
@@ -169,7 +165,7 @@ mca_search()
  * Set up the display to start a new toggle-option command.
  */
 	static void
-mca_opt_toggle()
+mca_opt_toggle(void)
 {
 	int no_prompt;
 	int flag;
@@ -204,9 +200,9 @@ mca_opt_toggle()
  * Execute a multicharacter command.
  */
 	static void
-exec_mca()
+exec_mca(void)
 {
-	register char *cbuf;
+	char *cbuf;
 
 	cmd_exec();
 	cbuf = get_cmdbuf();
@@ -294,8 +290,7 @@ exec_mca()
  * Is a character an erase or kill char?
  */
 	static int
-is_erase_char(c)
-	int c;
+is_erase_char(int c)
 {
 	return (c == erase_char || c == erase2_char || c == kill_char);
 }
@@ -304,8 +299,7 @@ is_erase_char(c)
  * Handle the first char of an option (after the initial dash).
  */
 	static int
-mca_opt_first_char(c)
-    int c;
+mca_opt_first_char(int c)
 {
 	int flag = (optflag & ~OPT_NO_PROMPT);
 	if (flag == OPT_NO_TOGGLE)
@@ -356,8 +350,7 @@ mca_opt_first_char(c)
  * accepting chars until user hits RETURN.
  */
 	static int
-mca_opt_nonfirst_char(c)
-	int c;
+mca_opt_nonfirst_char(int c)
 {
 	char *p;
 	char *oname;
@@ -406,8 +399,7 @@ mca_opt_nonfirst_char(c)
  * Handle a char of an option toggle command.
  */
 	static int
-mca_opt_char(c)
-	int c;
+mca_opt_char(int c)
 {
 	PARG parg;
 
@@ -472,8 +464,7 @@ mca_opt_char(c)
  * Handle a char of a search command.
  */
 	static int
-mca_search_char(c)
-	int c;
+mca_search_char(int c)
 {
 	int flag = 0;
 
@@ -525,8 +516,7 @@ mca_search_char(c)
  * Handle a character of a multi-character command.
  */
 	static int
-mca_char(c)
-	int c;
+mca_char(int c)
 {
 	int ret;
 
@@ -628,7 +618,7 @@ mca_char(c)
  * Discard any buffered file data.
  */
 	static void
-clear_buffers()
+clear_buffers(void)
 {
 	if (!(ch_getflags() & CH_CANSEEK))
 		return;
@@ -643,7 +633,7 @@ clear_buffers()
  * Make sure the screen is displayed.
  */
 	static void
-make_display()
+make_display(void)
 {
 	/*
 	 * If nothing is displayed yet, display starting from initial_scrpos.
@@ -683,9 +673,9 @@ make_display()
  * Display the appropriate prompt.
  */
 	static void
-prompt()
+prompt(void)
 {
-	register constant char *p;
+	constant char *p;
 
 	if (ungot != NULL && !ungot->ug_end_command)
 	{
@@ -760,7 +750,7 @@ prompt()
  * Display the less version message.
  */
 	public void
-dispversion()
+dispversion(void)
 {
 	PARG parg;
 
@@ -775,7 +765,7 @@ dispversion()
  * (characters previously given to ungetcc or ungetsc).
  */
 	public int
-getcc()
+getcc(void)
 {
 	if (ungot == NULL)
 	{
@@ -830,8 +820,7 @@ getcc()
  * The next getcc() will return this character.
  */
 	public void
-ungetcc(c)
-	int c;
+ungetcc(int c)
 {
 	struct ungot *ug = (struct ungot *) ecalloc(1, sizeof(struct ungot));
 
@@ -846,10 +835,9 @@ ungetcc(c)
  * The next sequence of getcc()'s will return this string.
  */
 	public void
-ungetsc(s)
-	char *s;
+ungetsc(char *s)
 {
-	register char *p;
+	char *p;
 
 	for (p = s + strlen(s) - 1;  p >= s;  p--)
 		ungetcc(*p);
@@ -861,12 +849,9 @@ ungetsc(s)
  * If SRCH_PAST_EOF is set, continue the search thru multiple files.
  */
 	static void
-multi_search(pattern, n, silent)
-	char *pattern;
-	int n;
-	int silent;
+multi_search(char *pattern, int n, int silent)
 {
-	register int nomore;
+	int nomore;
 	IFILE save_ifile;
 	int changed_file;
 
@@ -958,8 +943,7 @@ multi_search(pattern, n, silent)
  * Forward forever, or until a highlighted line appears.
  */
 	static int
-forw_loop(until_hilite)
-	int until_hilite;
+forw_loop(int until_hilite)
 {
 	POSITION curr_len;
 
@@ -999,11 +983,11 @@ forw_loop(until_hilite)
  * Accept and execute commands until a quit command.
  */
 	public void
-commands()
+commands(void)
 {
-	register int c;
-	register int action;
-	register char *cbuf;
+	int c;
+	int action;
+	char *cbuf;
 	int newaction;
 	int save_search_type;
 	char *extra;
diff --git a/cvt.c b/cvt.c
index d9836418e13f..0c0b08be5600 100644
--- a/cvt.c
+++ b/cvt.c
@@ -20,9 +20,7 @@ extern int utf_mode;
  * Get the length of a buffer needed to convert a string.
  */
 	public int
-cvt_length(len, ops)
-	int len;
-	int ops;
+cvt_length(int len, int ops)
 {
 	if (utf_mode)
 		/*
@@ -38,8 +36,7 @@ cvt_length(len, ops)
  * Allocate a chpos array for use by cvt_text.
  */
 	public int *
-cvt_alloc_chpos(len)
-	int len;
+cvt_alloc_chpos(int len)
 {
 	int i;
 	int *chpos = (int *) ecalloc(sizeof(int), len);
@@ -55,17 +52,12 @@ cvt_alloc_chpos(len)
  * odst character (when it was in osrc) is returned in the chpos array.
  */
 	public void
-cvt_text(odst, osrc, chpos, lenp, ops)
-	char *odst;
-	char *osrc;
-	int *chpos;
-	int *lenp;
-	int ops;
+cvt_text(char *odst, char *osrc, int *chpos, int *lenp, int ops)
 {
 	char *dst;
 	char *edst = odst;
 	char *src;
-	register char *src_end;
+	char *src_end;
 	LWCHAR ch;
 
 	if (lenp != NULL)
@@ -77,7 +69,7 @@ cvt_text(odst, osrc, chpos, lenp, ops)
 	{
 		int src_pos = (int) (src - osrc);
 		int dst_pos = (int) (dst - odst);
-		ch = step_char(&src, +1, src_end);
+		ch = step_char((constant char **)&src, +1, src_end);
 		if ((ops & CVT_BS) && ch == '\b' && dst > odst)
 		{
 			/* Delete backspace and preceding char. */
diff --git a/decode.c b/decode.c
index 1cd159973153..7f857fd52cee 100644
--- a/decode.c
+++ b/decode.c
@@ -229,13 +229,11 @@ static struct tablelist *list_sysvar_tables = NULL;
  * Expand special key abbreviations in a command table.
  */
 	static void
-expand_special_keys(table, len)
-	char *table;
-	int len;
+expand_special_keys(char *table, int len)
 {
-	register char *fm;
-	register char *to;
-	register int a;
+	char *fm;
+	char *to;
+	int a;
 	char *repl;
 	int klen;
 
@@ -290,7 +288,7 @@ expand_special_keys(table, len)
  * Initialize the command lists.
  */
 	public void
-init_cmds()
+init_cmds(void)
 {
 	/*
 	 * Add the default command tables.
@@ -320,12 +318,9 @@ init_cmds()
  * Add a command table.
  */
 	static int
-add_cmd_table(tlist, buf, len)
-	struct tablelist **tlist;
-	char *buf;
-	int len;
+add_cmd_table(struct tablelist **tlist, char *buf, int len)
 {
-	register struct tablelist *t;
+	struct tablelist *t;
 
 	if (len == 0)
 		return (0);
@@ -350,9 +345,7 @@ add_cmd_table(tlist, buf, len)
  * Add a command table.
  */
 	public void
-add_fcmd_table(buf, len)
-	char *buf;
-	int len;
+add_fcmd_table(char *buf, int len)
 {
 	if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
 		error("Warning: some commands disabled", NULL_PARG);
@@ -362,9 +355,7 @@ add_fcmd_table(buf, len)
  * Add an editing command table.
  */
 	public void
-add_ecmd_table(buf, len)
-	char *buf;
-	int len;
+add_ecmd_table(char *buf, int len)
 {
 	if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
 		error("Warning: some edit commands disabled", NULL_PARG);
@@ -374,10 +365,7 @@ add_ecmd_table(buf, len)
  * Add an environment variable table.
  */
 	static void
-add_var_table(tlist, buf, len)
-	struct tablelist **tlist;
-	char *buf;
-	int len;
+add_var_table(struct tablelist **tlist, char *buf, int len)
 {
 	if (add_cmd_table(tlist, buf, len) < 0)
 		error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
@@ -387,15 +375,11 @@ add_var_table(tlist, buf, len)
  * Search a single command table for the command string in cmd.
  */
 	static int
-cmd_search(cmd, table, endtable, sp)
-	char *cmd;
-	char *table;
-	char *endtable;
-	char **sp;
+cmd_search(char *cmd, char *table, char *endtable, char **sp)
 {
-	register char *p;
-	register char *q;
-	register int a;
+	char *p;
+	char *q;
+	int a;
 
 	*sp = NULL;
 	for (p = table, q = cmd;  p < endtable;  p++, q++)
@@ -479,13 +463,10 @@ cmd_search(cmd, table, endtable, sp)
  * The "extra" string, if any, is returned in sp.
  */
 	static int
-cmd_decode(tlist, cmd, sp)
-	struct tablelist *tlist;
-	char *cmd;
-	char **sp;
+cmd_decode(struct tablelist *tlist, char *cmd, char **sp)
 {
-	register struct tablelist *t;
-	register int action = A_INVALID;
+	struct tablelist *t;
+	int action = A_INVALID;
 
 	/*
 	 * Search thru all the command tables.
@@ -506,9 +487,7 @@ cmd_decode(tlist, cmd, sp)
  * Decode a command from the cmdtables list.
  */
 	public int
-fcmd_decode(cmd, sp)
-	char *cmd;
-	char **sp;
+fcmd_decode(char *cmd, char **sp)
 {
 	return (cmd_decode(list_fcmd_tables, cmd, sp));
 }
@@ -517,9 +496,7 @@ fcmd_decode(cmd, sp)
  * Decode a command from the edittables list.
  */
 	public int
-ecmd_decode(cmd, sp)
-	char *cmd;
-	char **sp;
+ecmd_decode(char *cmd, char **sp)
 {
 	return (cmd_decode(list_ecmd_tables, cmd, sp));
 }
@@ -529,8 +506,7 @@ ecmd_decode(cmd, sp)
  * Looks first in the lesskey file, then in the real environment.
  */
 	public char *
-lgetenv(var)
-	char *var;
+lgetenv(char *var)
 {
 	int a;
 	char *s;
@@ -554,8 +530,7 @@ lgetenv(var)
  * two bytes, low order first, in radix KRADIX.
  */
 	static int
-gint(sp)
-	char **sp;
+gint(char **sp)
 {
 	int n;
 
@@ -568,9 +543,7 @@ gint(sp)
  * Process an old (pre-v241) lesskey file.
  */
 	static int
-old_lesskey(buf, len)
-	char *buf;
-	int len;
+old_lesskey(char *buf, int len)
 {
 	/*
 	 * Old-style lesskey file.
@@ -589,14 +562,11 @@ old_lesskey(buf, len)
  * Process a new (post-v241) lesskey file.
  */
 	static int
-new_lesskey(buf, len, sysvar)
-	char *buf;
-	int len;
-	int sysvar;
+new_lesskey(char *buf, int len, int sysvar)
 {
 	char *p;
-	register int c;
-	register int n;
+	int c;
+	int n;
 
 	/*
 	 * New-style lesskey file.
@@ -643,14 +613,12 @@ new_lesskey(buf, len, sysvar)
  * Set up a user command table, based on a "lesskey" file.
  */
 	public int
-lesskey(filename, sysvar)
-	char *filename;
-	int sysvar;
+lesskey(char *filename, int sysvar)
 {
-	register char *buf;
-	register POSITION len;
-	register long n;
-	register int f;
+	char *buf;
+	POSITION len;
+	long n;
+	int f;
 
 	if (secure)
 		return (1);
@@ -713,10 +681,7 @@ lesskey(filename, sysvar)
  * Add the standard lesskey file "$HOME/.less"
  */
 	public void
-add_hometable(envname, def_filename, sysvar)
-	char *envname;
-	char *def_filename;
-	int sysvar;
+add_hometable(char *envname, char *def_filename, int sysvar)
 {
 	char *filename;
 	PARG parg;
@@ -742,9 +707,7 @@ add_hometable(envname, def_filename, sysvar)
  * See if a char is a special line-editing command.
  */
 	public int
-editchar(c, flags)
-	int c;
-	int flags;
+editchar(int c, int flags)
 {
 	int action;
 	int nch;
diff --git a/edit.c b/edit.c
index 2a35adec48d2..9a89314ef13d 100644
--- a/edit.c
+++ b/edit.c
@@ -26,7 +26,7 @@ extern int sigs;
 extern IFILE curr_ifile;
 extern IFILE old_ifile;
 extern struct scrpos initial_scrpos;
-extern void constant *ml_examine;
+extern void * constant ml_examine;
 #if SPACES_IN_FILENAMES
 extern char openquote;
 extern char closequote;
@@ -55,9 +55,7 @@ static void *curr_altpipe;
  * back_textlist does the same, but runs thru the list backwards.
  */
 	public void
-init_textlist(tlist, str)
-	struct textlist *tlist;
-	char *str;
+init_textlist(struct textlist *tlist, char *str)
 {
 	char *s;
 #if SPACES_IN_FILENAMES
@@ -99,9 +97,7 @@ init_textlist(tlist, str)
 }
 
 	public char *
-forw_textlist(tlist, prev)
-	struct textlist *tlist;
-	char *prev;
+forw_textlist(struct textlist *tlist, char *prev)
 {
 	char *s;
 	
@@ -123,9 +119,7 @@ forw_textlist(tlist, prev)
 }
 
 	public char *
-back_textlist(tlist, prev)
-	struct textlist *tlist;
-	char *prev;
+back_textlist(struct textlist *tlist, char *prev)
 {
 	char *s;
 	
@@ -152,7 +146,7 @@ back_textlist(tlist, prev)
  * Close the current input file.
  */
 	static void
-close_file()
+close_file(void)
 {
 	struct scrpos scrpos;
 	
@@ -196,8 +190,7 @@ close_file()
  * Filename == NULL means just close the current file.
  */
 	public int
-edit(filename)
-	char *filename;
+edit(char *filename)
 {
 	if (filename == NULL)
 		return (edit_ifile(NULL_IFILE));
@@ -209,8 +202,7 @@ edit(filename)
  * ifile == NULL means just close the current file.
  */
 	public int
-edit_ifile(ifile)
-	IFILE ifile;
+edit_ifile(IFILE ifile)
 {
 	int f;
 	int answer;
@@ -460,8 +452,7 @@ edit_ifile(ifile)
  * Then edit the first one.
  */
 	public int
-edit_list(filelist)
-	char *filelist;
+edit_list(char *filelist)
 {
 	IFILE save_ifile;
 	char *good_filename;
@@ -518,7 +509,7 @@ edit_list(filelist)
  * Edit the first file in the command line (ifile) list.
  */
 	public int
-edit_first()
+edit_first(void)
 {
 	curr_ifile = NULL_IFILE;
 	return (edit_next(1));
@@ -528,7 +519,7 @@ edit_first()
  * Edit the last file in the command line (ifile) list.
  */
 	public int
-edit_last()
+edit_last(void)
 {
 	curr_ifile = NULL_IFILE;
 	return (edit_prev(1));
@@ -539,10 +530,7 @@ edit_last()
  * Edit the n-th next or previous file in the command line (ifile) list.
  */
 	static int
-edit_istep(h, n, dir)
-	IFILE h;
-	int n;
-	int dir;
+edit_istep(IFILE h, int n, int dir)
 {
 	IFILE next;
 
@@ -581,31 +569,25 @@ edit_istep(h, n, dir)
 }
 
 	static int
-edit_inext(h, n)
-	IFILE h;
-	int n;
+edit_inext(IFILE h, int n)
 {
 	return (edit_istep(h, n, +1));
 }
 
 	public int
-edit_next(n)
-	int n;
+edit_next(int n)
 {
 	return edit_istep(curr_ifile, n, +1);
 }
 
 	static int
-edit_iprev(h, n)
-	IFILE h;
-	int n;
+edit_iprev(IFILE h, int n)
 {
 	return (edit_istep(h, n, -1));
 }
 
 	public int
-edit_prev(n)
-	int n;
+edit_prev(int n)
 {
 	return edit_istep(curr_ifile, n, -1);
 }
@@ -614,8 +596,7 @@ edit_prev(n)
  * Edit a specific file in the command line (ifile) list.
  */
 	public int
-edit_index(n)
-	int n;
+edit_index(int n)
 {
 	IFILE h;
 
@@ -635,7 +616,7 @@ edit_index(n)
 }
 
 	public IFILE
-save_curr_ifile()
+save_curr_ifile(void)
 {
 	if (curr_ifile != NULL_IFILE)
 		hold_ifile(curr_ifile, 1);
@@ -643,8 +624,7 @@ save_curr_ifile()
 }
 
 	public void
-unsave_ifile(save_ifile)
-	IFILE save_ifile;
+unsave_ifile(IFILE save_ifile)
 {
 	if (save_ifile != NULL_IFILE)
 		hold_ifile(save_ifile, -1);
@@ -654,8 +634,7 @@ unsave_ifile(save_ifile)
  * Reedit the ifile which was previously open.
  */
 	public void
-reedit_ifile(save_ifile)
-	IFILE save_ifile;
+reedit_ifile(IFILE save_ifile)
 {
 	IFILE next;
 	IFILE prev;
@@ -688,7 +667,7 @@ reedit_ifile(save_ifile)
 }
 
 	public void
-reopen_curr_ifile()
+reopen_curr_ifile(void)
 {
 	IFILE save_ifile = save_curr_ifile();
 	close_file();
@@ -699,7 +678,7 @@ reopen_curr_ifile()
  * Edit standard input.
  */
 	public int
-edit_stdin()
+edit_stdin(void)
 {
 	if (isatty(fd0))
 	{
@@ -714,9 +693,9 @@ edit_stdin()
  * Used if standard output is not a tty.
  */
 	public void
-cat_file()
+cat_file(void)
 {
-	register int c;
+	int c;
 
 	while ((c = ch_forw_get()) != EOI)
 		putchr(c);
@@ -731,11 +710,10 @@ cat_file()
  * We take care not to blindly overwrite an existing file.
  */
 	public void
-use_logfile(filename)
-	char *filename;
+use_logfile(char *filename)
 {
-	register int exists;
-	register int answer;
+	int exists;
+	int answer;
 	PARG parg;
 
 	if (ch_getflags() & CH_CANSEEK)
diff --git a/filename.c b/filename.c
index 9631f1c2b3d8..715a96a85a78 100644
--- a/filename.c
+++ b/filename.c
@@ -63,8 +63,7 @@ extern char closequote;
  * Remove quotes around a filename.
  */
 	public char *
-shell_unquote(str)
-	char *str;
+shell_unquote(char *str)
 {
 	char *name;
 	char *p;
@@ -102,7 +101,7 @@ shell_unquote(str)
  * Get the shell's escape character.
  */
 	public char *
-get_meta_escape()
+get_meta_escape(void)
 {
 	char *s;
 
@@ -116,7 +115,7 @@ get_meta_escape()
  * Get the characters which the shell considers to be "metacharacters".
  */
 	static char *
-metachars()
+metachars(void)
 {
 	static char *mchars = NULL;
 
@@ -133,8 +132,7 @@ metachars()
  * Is this a shell metacharacter?
  */
 	static int
-metachar(c)
-	char c;
+metachar(char c)
 {
 	return (strchr(metachars(), c) != NULL);
 }
@@ -143,8 +141,7 @@ metachar(c)
  * Insert a backslash before each metacharacter in a string.
  */
 	public char *
-shell_quote(s)
-	char *s;
+shell_quote(char *s)
 {
 	char *p;
 	char *newstr;
@@ -221,9 +218,7 @@ shell_quote(s)
  * Return NULL if the file does not exist in the directory.
  */
 	static char *
-dirfile(dirname, filename)
-	char *dirname;
-	char *filename;
+dirfile(char *dirname, char *filename)
 {
 	char *pathname;
 	char *qpathname;
@@ -261,10 +256,9 @@ dirfile(dirname, filename)
  * Return the full pathname of the given file in the "home directory".
  */
 	public char *
-homefile(filename)
-	char *filename;
+homefile(char *filename)
 {
-	register char *pathname;
+	char *pathname;
 
 	/*
 	 * Try $HOME/filename.
@@ -311,12 +305,11 @@ homefile(filename)
  * {{ This is a lot of work just to support % and #. }}
  */
 	public char *
-fexpand(s)
-	char *s;
+fexpand(char *s)
 {
-	register char *fr, *to;
-	register int n;
-	register char *e;
+	char *fr, *to;
+	int n;
+	char *e;
 	IFILE ifile;
 
 #define	fchar_ifile(c) \
@@ -407,8 +400,7 @@ fexpand(s)
  * the given string.
  */
 	public char *
-fcomplete(s)
-	char *s;
+fcomplete(char *s)
 {
 	char *fpat;
 	char *qs;
@@ -467,13 +459,12 @@ fcomplete(s)
  * This is just a guess, and we need not try too hard to make it accurate.
  */
 	public int
-bin_file(f)
-	int f;
+bin_file(int f)
 {
 	int n;
 	int bin_count = 0;
 	char data[256];
-	char* p;
+	constant char* p;
 	char* pend;
 
 	if (!seekable(f))
@@ -512,8 +503,7 @@ bin_file(f)
  * Try to determine the size of a file by seeking to the end.
  */
 	static POSITION
-seek_filesize(f)
-	int f;
+seek_filesize(int f)
 {
 	off_t spos;
 
@@ -528,8 +518,7 @@ seek_filesize(f)
  * Return a pointer to the string in memory.
  */
 	static char *
-readfd(fd)
-	FILE *fd;
+readfd(FILE *fd)
 {
 	int len;
 	int ch;
@@ -577,8 +566,7 @@ FILE *popen();
  * Return a pointer to a pipe connected to the shell command's standard output.
  */
 	static FILE *
-shellcmd(cmd)
-	char *cmd;
+shellcmd(char *cmd)
 {
 	FILE *fd;
 
@@ -628,8 +616,7 @@ shellcmd(cmd)
  * Expand a filename, doing any system-specific metacharacter substitutions.
  */
 	public char *
-lglob(filename)
-	char *filename;
+lglob(char *filename)
 {
 	char *gfilename;
 	char *ofilename;
@@ -690,9 +677,9 @@ lglob(filename)
 	 * The globbing function returns a single name, and
 	 * is called multiple times to walk thru all names.
 	 */
-	register char *p;
-	register int len;
-	register int n;
+	char *p;
+	int len;
+	int n;
 	char *pathname;
 	char *qpathname;
 	DECL_GLOB_NAME(fnd,drive,dir,fname,ext,handle)
@@ -818,8 +805,7 @@ lglob(filename)
  * Return a large number if there are any other % escapes besides %s.
  */
 	static int
-num_pct_s(lessopen)
-	char *lessopen;
+num_pct_s(char *lessopen)
 {
 	int num = 0;
 
@@ -844,10 +830,7 @@ num_pct_s(lessopen)
  * instead of the file we're about to open.
  */
 	public char *
-open_altfile(filename, pf, pfd)
-	char *filename;
-	int *pf;
-	void **pfd;
+open_altfile(char *filename, int *pf, void **pfd)
 {
 #if !HAVE_POPEN
 	return (NULL);
@@ -956,10 +939,7 @@ open_altfile(filename, pf, pfd)
  * Close a replacement file.
  */
 	public void
-close_altfile(altfilename, filename, pipefd)
-	char *altfilename;
-	char *filename;
-	void *pipefd;
+close_altfile(char *altfilename, char *filename, void *pipefd)
 {
 #if HAVE_POPEN
 	char *lessclose;
@@ -1001,8 +981,7 @@ close_altfile(altfilename, filename, pipefd)
  * Is the specified file a directory?
  */
 	public int
-is_dir(filename)
-	char *filename;
+is_dir(char *filename)
 {
 	int isdir = 0;
 
@@ -1018,7 +997,7 @@ is_dir(filename)
 #else
 #ifdef _OSK
 {
-	register int f;
+	int f;
 
 	f = open(filename, S_IREAD | S_IFDIR);
 	if (f >= 0)
@@ -1037,10 +1016,9 @@ is_dir(filename)
  * (if it cannot be opened or is a directory, etc.)
  */
 	public char *
-bad_file(filename)
-	char *filename;
+bad_file(char *filename)
 {
-	register char *m = NULL;
+	char *m = NULL;
 
 	filename = shell_unquote(filename);
 	if (!force_open && is_dir(filename))
@@ -1083,8 +1061,7 @@ bad_file(filename)
  * In Unix, we can stat the file.
  */
 	public POSITION
-filesize(f)
-	int f;
+filesize(int f)
 {
 #if HAVE_STAT
 	struct stat statbuf;
@@ -1106,7 +1083,7 @@ filesize(f)
  * 
  */
 	public char *
-shell_coption()
+shell_coption(void)
 {
 	return ("-c");
 }
@@ -1115,8 +1092,7 @@ shell_coption()
  * Return last component of a pathname.
  */
 	public char *
-last_component(name)
-	char *name;
+last_component(char *name)
 {
 	char *slash;
 
diff --git a/forwback.c b/forwback.c
index 721a0286a7b8..056f4752701c 100644
--- a/forwback.c
+++ b/forwback.c
@@ -46,7 +46,7 @@ extern char *tagoption;
  * Sound the bell to indicate user is trying to move past end of file.
  */
 	static void
-eof_bell()
+eof_bell(void)
 {
 	if (quiet == NOT_QUIET)
 		bell();
@@ -58,7 +58,7 @@ eof_bell()
  * Check to see if the end of file is currently displayed.
  */
 	public int
-eof_displayed()
+eof_displayed(void)
 {
 	POSITION pos;
 
@@ -85,7 +85,7 @@ eof_displayed()
  * Check to see if the entire file is currently displayed.
  */
 	public int
-entire_file_displayed()
+entire_file_displayed(void)
 {
 	POSITION pos;
 
@@ -105,7 +105,7 @@ entire_file_displayed()
  * for the first time.
  */
 	public void
-squish_check()
+squish_check(void)
 {
 	if (!squished)
 		return;
@@ -123,12 +123,7 @@ squish_check()
  *   The first real line after the blanks will start at ch_zero().
  */
 	public void
-forw(n, pos, force, only_last, nblank)
-	register int n;
-	POSITION pos;
-	int force;
-	int only_last;
-	int nblank;
+forw(int n, POSITION pos, int force, int only_last, int nblank)
 {
 	int nlines = 0;
 	int do_repaint;
@@ -297,11 +292,7 @@ forw(n, pos, force, only_last, nblank)
  * Display n lines, scrolling backward.
  */
 	public void
-back(n, pos, force, only_last)
-	register int n;
-	POSITION pos;
-	int force;
-	int only_last;
+back(int n, POSITION pos, int force, int only_last)
 {
 	int nlines = 0;
 	int do_repaint;
@@ -359,10 +350,7 @@ back(n, pos, force, only_last)
  * Start just after the line currently displayed at the bottom of the screen.
  */
 	public void
-forward(n, force, only_last)
-	int n;
-	int force;
-	int only_last;
+forward(int n, int force, int only_last)
 {
 	POSITION pos;
 
@@ -411,10 +399,7 @@ forward(n, force, only_last)
  * Start just before the line currently displayed at the top of the screen.
  */
 	public void
-backward(n, force, only_last)
-	int n;
-	int force;
-	int only_last;
+backward(int n, int force, int only_last)
 {
 	POSITION pos;
 
@@ -434,7 +419,7 @@ backward(n, force, only_last)
  * top_scroll, as well as back_scroll.
  */
 	public int
-get_back_scroll()
+get_back_scroll(void)
 {
 	if (no_back_scroll)
 		return (0);
diff --git a/funcs.h b/funcs.h
index 53550f0cc46f..fa8ecc345cdb 100644
--- a/funcs.h
+++ b/funcs.h
@@ -1,298 +1,302 @@
-	public char * save ();
-	public VOID_POINTER ecalloc ();
-	public char * skipsp ();
-	public int sprefix ();
-	public void quit ();
-	public void raw_mode ();
-	public void scrsize ();
-	public char * special_key_str ();
-	public void get_term ();
-	public void init ();
-	public void deinit ();
-	public void home ();
-	public void add_line ();
-	public void remove_top ();
-	public void win32_scroll_up ();
-	public void lower_left ();
-	public void line_left ();
-	public void check_winch ();
-	public void goto_line ();
-	public void vbell ();
-	public void bell ();
-	public void clear ();
-	public void clear_eol ();
-	public void clear_bot ();
-	public void at_enter ();
-	public void at_exit ();
-	public void at_switch ();
-	public int is_at_equiv ();
-	public int apply_at_specials ();
-	public void backspace ();
-	public void putbs ();
-	public char WIN32getch ();
-	public void WIN32setcolors ();
-	public void WIN32textout ();
-	public void match_brac ();
-	public void ch_ungetchar ();
-	public void end_logfile ();
-	public void sync_logfile ();
-	public int ch_seek ();
-	public int ch_end_seek ();
-	public int ch_end_buffer_seek ();
-	public int ch_beg_seek ();
-	public POSITION ch_length ();
-	public POSITION ch_tell ();
-	public int ch_forw_get ();
-	public int ch_back_get ();
-	public void ch_setbufspace ();
-	public void ch_flush ();
-	public int seekable ();
-	public void ch_set_eof ();
-	public void ch_init ();
-	public void ch_close ();
-	public int ch_getflags ();
-	public void ch_dump ();
-	public void init_charset ();
-	public int binary_char ();
-	public int control_char ();
-	public char * prchar ();
-	public char * prutfchar ();
-	public int utf_len ();
-	public int is_utf8_well_formed ();
-	public int utf_bin_count ();
-	public LWCHAR get_wchar ();
-	public void put_wchar ();
-	public LWCHAR step_char ();
-	public int is_composing_char ();
-	public int is_ubin_char ();
-	public int is_wide_char ();
-	public int is_combining_char ();
-	public void cmd_reset ();
-	public void clear_cmd ();
-	public void cmd_putstr ();
-	public int len_cmdbuf ();
-	public void set_mlist ();
-	public void cmd_addhist ();
-	public void cmd_accept ();
-	public int cmd_char ();
-	public LINENUM cmd_int ();
-	public char * get_cmdbuf ();
-	public char * cmd_lastpattern ();
-	public void init_cmdhist ();
-	public void save_cmdhist ();
-	public int in_mca ();
-	public void dispversion ();
-	public int getcc ();
-	public void ungetcc ();
-	public void ungetsc ();
-	public void commands ();
-	public int cvt_length ();
-	public int * cvt_alloc_chpos ();
-	public void cvt_text ();
-	public void init_cmds ();
-	public void add_fcmd_table ();
-	public void add_ecmd_table ();
-	public int fcmd_decode ();
-	public int ecmd_decode ();
-	public char * lgetenv ();
-	public int lesskey ();
-	public void add_hometable ();
-	public int editchar ();
-	public void init_textlist ();
-	public char * forw_textlist ();
-	public char * back_textlist ();
-	public int edit ();
-	public int edit_ifile ();
-	public int edit_list ();
-	public int edit_first ();
-	public int edit_last ();
-	public int edit_next ();
-	public int edit_prev ();
-	public int edit_index ();
-	public IFILE save_curr_ifile ();
-	public void unsave_ifile ();
-	public void reedit_ifile ();
-	public void reopen_curr_ifile ();
-	public int edit_stdin ();
-	public void cat_file ();
-	public void use_logfile ();
-	public char * shell_unquote ();
-	public char * get_meta_escape ();
-	public char * shell_quote ();
-	public char * homefile ();
-	public char * fexpand ();
-	public char * fcomplete ();
-	public int bin_file ();
-	public char * lglob ();
-	public char * open_altfile ();
-	public void close_altfile ();
-	public int is_dir ();
-	public char * bad_file ();
-	public POSITION filesize ();
-	public char * shell_coption ();
-	public char * last_component ();
-	public int eof_displayed ();
-	public int entire_file_displayed ();
-	public void squish_check ();
-	public void forw ();
-	public void back ();
-	public void forward ();
-	public void backward ();
-	public int get_back_scroll ();
-	public void del_ifile ();
-	public IFILE next_ifile ();
-	public IFILE prev_ifile ();
-	public IFILE getoff_ifile ();
-	public int nifile ();
-	public IFILE get_ifile ();
-	public char * get_filename ();
-	public int get_index ();
-	public void store_pos ();
-	public void get_pos ();
-	public void set_open ();
-	public int opened ();
-	public void hold_ifile ();
-	public int held_ifile ();
-	public void * get_filestate ();
-	public void set_filestate ();
-	public void if_dump ();
-	public POSITION forw_line ();
-	public POSITION back_line ();
-	public void set_attnpos ();
-	public void jump_forw ();
-	public void jump_forw_buffered ();
-	public void jump_back ();
-	public void repaint ();
-	public void jump_percent ();
-	public void jump_line_loc ();
-	public void jump_loc ();
-	public void init_line ();
-	public int is_ascii_char ();
-	public void prewind ();
-	public void plinenum ();
-	public void pshift_all ();
-	public int is_ansi_end ();
-	public int is_ansi_middle ();
-	public int pappend ();
-	public int pflushmbc ();
-	public void pdone ();
-	public void set_status_col ();
-	public int gline ();
-	public void null_line ();
-	public POSITION forw_raw_line ();
-	public POSITION back_raw_line ();
-	public void clr_linenum ();
-	public void add_lnum ();
-	public LINENUM find_linenum ();
-	public POSITION find_pos ();
-	public LINENUM currline ();
-	public void lsystem ();
-	public int pipe_mark ();
-	public int pipe_data ();
-	public void init_mark ();
-	public int badmark ();
-	public void setmark ();
-	public void lastmark ();
-	public void gomark ();
-	public POSITION markpos ();
-	public void unmark ();
-	public void opt_o ();
-	public void opt__O ();
-	public void opt_j ();
-	public void calc_jump_sline ();
-	public void opt_shift ();
-	public void calc_shift_count ();
-	public void opt_k ();
-	public void opt_t ();
-	public void opt__T ();
-	public void opt_p ();
-	public void opt__P ();
-	public void opt_b ();
-	public void opt_i ();
-	public void opt__V ();
-	public void opt_D ();
-	public void opt_x ();
-	public void opt_quote ();
-	public void opt_query ();
-	public int get_swindow ();
-	public char * propt ();
-	public void scan_option ();
-	public void toggle_option ();
-	public int opt_has_param ();
-	public char * opt_prompt ();
-	public int isoptpending ();
-	public void nopendopt ();
-	public int getnum ();
-	public long getfraction ();
-	public int get_quit_at_eof ();
-	public void init_option ();
-	public struct loption * findopt ();
-	public struct loption * findopt_name ();
-	public int iread ();
-	public void intread ();
-	public time_type get_time ();
-	public char * errno_message ();
-	public int percentage ();
-	public POSITION percent_pos ();
-	public int  os9_signal ();
-	public void put_line ();
-	public void flush ();
-	public int putchr ();
-	public void putstr ();
-	public void get_return ();
-	public void error ();
-	public void ierror ();
-	public int query ();
-	public int compile_pattern ();
-	public void uncompile_pattern ();
-	public int valid_pattern ();
-	public int is_null_pattern ();
-	public int match_pattern ();
-	public POSITION position ();
-	public void add_forw_pos ();
-	public void add_back_pos ();
-	public void pos_clear ();
-	public void pos_init ();
-	public int onscreen ();
-	public int empty_screen ();
-	public int empty_lines ();
-	public void get_scrpos ();
-	public int adjsline ();
-	public void init_prompt ();
-	public char * pr_expand ();
-	public char * eq_message ();
-	public char * pr_string ();
-	public char * wait_message ();
-	public void init_search ();
-	public void repaint_hilite ();
-	public void clear_attn ();
-	public void undo_search ();
-	public void clr_hlist ();
-	public void clr_hilite ();
-	public void clr_filter ();
-	public int is_filtered ();
-	public POSITION next_unfiltered ();
-	public POSITION prev_unfiltered ();
-	public int is_hilited ();
-	public void chg_caseless ();
-	public void chg_hilite ();
-	public int search ();
-	public void prep_hilite ();
-	public void set_filter_pattern ();
-	public int is_filtering ();
-	public RETSIGTYPE winch ();
-	public RETSIGTYPE winch ();
-	public void init_signals ();
-	public void psignals ();
-	public void cleantags ();
-	public int gettagtype ();
-	public void findtag ();
-	public POSITION tagsearch ();
-	public char * nexttag ();
-	public char * prevtag ();
-	public int ntags ();
-	public int curr_tag ();
-	public int edit_tagfile ();
-	public void open_getchr ();
-	public void close_getchr ();
-	public int getchr ();
+	public char * save (constant char *s);
+	public VOID_POINTER ecalloc (int count, unsigned int size);
+	public char * skipsp (char *s);
+	public char * skipnsp(char *s);
+	public int sprefix (char *ps, char *s, int uppercase);
+	public void quit (int status);
+	public void raw_mode (int on);
+	public void scrsize (void);
+	public char * special_key_str (int key);
+	public void get_term (void);
+	public void init (void);
+	public void deinit (void);
+	public void home (void);
+	public void add_line (void);
+	public void remove_top (int n);
+	public void win32_scroll_up (int n);
+	public void lower_left (void);
+	public void line_left (void);
+	public void check_winch (void);
+	public void goto_line (int slinenum);
+	public void vbell (void);
+	public void bell (void);
+	public void clear (void);
+	public void clear_eol (void);
+	public void clear_bot (void);
+	public void at_enter (int attr);
+	public void at_exit (void);
+	public void at_switch (int attr);
+	public int is_at_equiv (int attr1, int attr2);
+	public int apply_at_specials (int attr);
+	public void backspace (void);
+	public void putbs (void);
+	public char WIN32getch (int tty);
+	public void WIN32setcolors (int fg, int bg);
+	public void WIN32textout (char *text, int len);
+	public void match_brac(int obrac, int cbrac, int forwdir, int n);
+	public void ch_ungetchar (int c);
+	public void end_logfile (void);
+	public void sync_logfile (void);
+	public int ch_seek (POSITION pos);
+	public int ch_end_seek (void);
+	public int ch_end_buffer_seek (void);
+	public int ch_beg_seek (void);
+	public POSITION ch_length (void);
+	public POSITION ch_tell (void);
+	public int ch_forw_get (void);
+	public int ch_back_get (void);
+	public void ch_setbufspace (int bufspace);
+	public void ch_flush (void);
+	public int seekable (int f);
+	public void ch_set_eof (void);
+	public void ch_init (int f, int flags);
+	public void ch_close (void);
+	public int ch_getflags (void);
+struct filestate;
+	public void ch_dump (struct filestate *fs);
+	public void init_charset (void);
+	public int binary_char (LWCHAR c);
+	public int control_char (LWCHAR c);
+	public char * prchar (LWCHAR c);
+	public char * prutfchar (LWCHAR ch);
+	public int utf_len (char ch);
+	public int is_utf8_well_formed (unsigned char *s, int slen);
+	public int utf_bin_count (unsigned char *data, int len);
+	public LWCHAR get_wchar (constant char *p);
+	public void put_wchar (char **pp, LWCHAR ch);
+	public LWCHAR step_char (constant char **pp, signed int dir, constant char *limit);
+	public int is_composing_char (LWCHAR ch);
+	public int is_ubin_char (LWCHAR ch);
+	public int is_wide_char (LWCHAR ch);
+	public int is_combining_char (LWCHAR ch1, LWCHAR ch2);
+	public void cmd_reset (void);
+	public void clear_cmd (void);
+	public void cmd_putstr (constant char *s);
+	public int len_cmdbuf (void);
+	public void set_mlist (constant void *mlist, int cmdflags);
+struct mlist;
+	public void cmd_addhist (struct mlist *constant mlist, char *cmd, int modified);
+	public void cmd_accept (void);
+	public int cmd_char (int c);
+	public LINENUM cmd_int (long *frac);
+	public char * get_cmdbuf (void);
+	public char * cmd_lastpattern (void);
+	public void init_cmdhist (void);
+	public void save_cmdhist (void);
+	public int in_mca (void);
+	public void dispversion (void);
+	public int getcc (void);
+	public void ungetcc (int c);
+	public void ungetsc (char *s);
+	public void commands (void);
+	public int cvt_length (int len, int ops);
+	public int * cvt_alloc_chpos (int len);
+	public void cvt_text (char *odst, char *osrc, int *chpos, int *lenp, int ops);
+	public void init_cmds (void);
+	public void add_fcmd_table (char *buf, int len);
+	public void add_ecmd_table (char *buf, int len);
+	public int fcmd_decode (char *cmd, char **sp);
+	public int ecmd_decode (char *cmd, char **sp);
+	public char * lgetenv (char *var);
+	public int lesskey (char *filename, int sysvar);
+	public void add_hometable (char *envname, char *def_filename, int sysvar);
+	public int editchar (int c, int flags);
+	public void init_textlist (struct textlist *tlist, char *str);
+	public char * forw_textlist (struct textlist *tlist, char *prev);
+	public char * back_textlist (struct textlist *tlist, char *prev);
+	public int edit (char *filename);
+	public int edit_ifile (IFILE ifile);
+	public int edit_list (char *filelist);
+	public int edit_first (void);
+	public int edit_last (void);
+	public int edit_next (int n);
+	public int edit_prev (int n);
+	public int edit_index (int n);
+	public IFILE save_curr_ifile (void);
+	public void unsave_ifile (IFILE save_ifile);
+	public void reedit_ifile (IFILE save_ifiler);
+	public void reopen_curr_ifile (void);
+	public int edit_stdin (void);
+	public void cat_file (void);
+	public void use_logfile (char *filename);
+	public char * shell_unquote (char *str);
+	public char * get_meta_escape (void);
+	public char * shell_quote (char *s);
+	public char * homefile (char *filename);
+	public char * fexpand (char *s);
+	public char * fcomplete (char *s);
+	public int bin_file (int f);
+	public char * lglob (char *filename);
+	public char * open_altfile (char *filename, int *pf, void **pfd);
+	public void close_altfile (char *altfilename, char *filename, void *pipefd);
+	public int is_dir (char *filename);
+	public char * bad_file (char *filename);
+	public POSITION filesize (int f);
+	public char * shell_coption (void);
+	public char * last_component (char *name);
+	public int eof_displayed (void);
+	public int entire_file_displayed (void);
+	public void squish_check (void);
+	public void forw (int n, POSITION pos, int force, int only_last, int nblank);
+	public void back (int n, POSITION pos, int force, int only_last);
+	public void forward (int n, int force, int only_last);
+	public void backward (int n, int force, int only_last);
+	public int get_back_scroll (void);
+	public void del_ifile (IFILE h);
+	public IFILE next_ifile (IFILE h);
+	public IFILE prev_ifile (IFILE h);
+	public IFILE getoff_ifile (IFILE ifile);
+	public int nifile (void);
+	public IFILE get_ifile (char *filename, IFILE prev);
+	public char * get_filename (IFILE ifile);
+	public int get_index (IFILE ifile);
+	public void store_pos (IFILE ifile, struct scrpos *scrpos);
+	public void get_pos (IFILE ifile, struct scrpos *scrpos);
+	public void set_open (IFILE ifile);
+	public int opened (IFILE ifile);
+	public void hold_ifile (IFILE ifile, int incr);
+	public int held_ifile (IFILE ifile);
+	public void * get_filestate (IFILE ifile);
+	public void set_filestate (IFILE ifile, void *filestate);
+	public void if_dump (void);
+	public POSITION forw_line (POSITION curr_pos);
+	public POSITION back_line (POSITION curr_pos);
+	public void set_attnpos (POSITION pos);
+	public void jump_forw (void);
+	public void jump_forw_buffered (void);
+	public void jump_back (LINENUM linenum);
+	public void repaint (void);
+	public void jump_percent (int percent, long fraction);
+	public void jump_line_loc (POSITION pos, int sline);
+	public void jump_loc (POSITION pos, int sline);
+	public void init_line (void);
+	public int is_ascii_char (LWCHAR ch);
+	public void prewind (void);
+	public void plinenum (POSITION pos);
+	public void pshift_all (void);
+	public int is_ansi_end (LWCHAR ch);
+	public int is_ansi_middle (LWCHAR ch);
+	public int pappend (unsigned char c, POSITION pos);
+	public int pflushmbc (void);
+	public void pdone (int endline, int forw);
+	public void set_status_col (char c);
+	public int gline (int i, int *ap);
+	public void null_line (void);
+	public POSITION forw_raw_line (POSITION curr_pos, char **linep, int *line_lenp);
+	public POSITION back_raw_line (POSITION curr_pos, char **linep, int *line_lenp);
+	public void clr_linenum (void);
+	public void add_lnum (LINENUM linenum, POSITION pos);
+	public LINENUM find_linenum (POSITION pos);
+	public POSITION find_pos (LINENUM linenum);
+	public LINENUM currline (int where);
+	public void lsystem (char *cmd, char *donemsg);
+	public int pipe_mark (int c, char *cmd);
+	public int pipe_data (char *cmd, POSITION spos, POSITION epos);
+	public void init_mark (void);
+	public int badmark (int c);
+	public void setmark (int c);
+	public void lastmark (void);
+	public void gomark (int c);
+	public POSITION markpos (int c);
+	public void unmark (IFILE ifile);
+	public void opt_o (int type, char *s);
+	public void opt__O (int type, char *s);
+	public void opt_j (int type, char *s);
+	public void calc_jump_sline (void);
+	public void opt_shift (int type, char *s);
+	public void calc_shift_count (void);
+	public void opt_k (int type, char *s);
+	public void opt_t (int type, char *s);
+	public void opt__T (int type, char *s);
+	public void opt_p (int type, char *s);
+	public void opt__P (int type, char *s);
+	public void opt_b (int type, char *s);
+	public void opt_i (int type, char *s);
+	public void opt__V (int type, char *s);
+	public void opt_D (int type, char *s);
+	public void opt_x (int type, char *s);
+	public void opt_quote (int type, char *s);
+	public void opt_query (int type, char *s);
+	public int get_swindow (void);
+	public char * propt (int c);
+	public void scan_option (char *s);
+struct loption;
+	public void toggle_option (struct loption *o, int lower, char *s, int how_toggle);
+	public int opt_has_param (struct loption *o);
+	public char * opt_prompt (struct loption *o);
+	public int isoptpending (void);
+	public void nopendopt (void);
+	public int getnum (char **sp, char *printopt, int *errp);
+	public long getfraction (char **sp, char *printopt, int *errp);
+	public int get_quit_at_eof (void);
+	public void init_option (void);
+	public struct loption * findopt (int c);
+	public struct loption * findopt_name (char **p_optname, char **p_oname, int *p_err);
+	public int iread (int fd, char *buf, unsigned int len);
+	public void intread (void);
+	public time_type get_time (void);
+	public char * errno_message (char *filename);
+	public int percentage (POSITION num, POSITION den);
+	public POSITION percent_pos (POSITION pos, int percent, long fraction);
+	public int  os9_signal (int type, RETSIGTYPE (*handler)());
+	public void put_line (void);
+	public void flush (void);
+	public int putchr (int c);
+	public void putstr (constant char *s);
+	public void get_return (void);
+	public void error (char *fmt, PARG *parg);
+	public void ierror (char *fmt, PARG *parg);
+	public int query (char *fmt, PARG *parg);
+	public int compile_pattern (char *pattern, int search_type, void **comp_pattern);
+	public void uncompile_pattern (void **pattern);
+	public int valid_pattern (char *pattern);
+	public int is_null_pattern (void *pattern);
+	public int match_pattern (void *pattern, char *tpattern, char *line, int line_len, char **sp, char **ep, int notbol, int search_type);
+	public POSITION position (int where);
+	public void add_forw_pos (POSITION pos);
+	public void add_back_pos (POSITION pos);
+	public void pos_clear (void);
+	public void pos_init (void);
+	public int onscreen (POSITION pos);
+	public int empty_screen (void);
+	public int empty_lines (int s, int e);
+	public void get_scrpos (struct scrpos *scrpos);
+	public int adjsline (int sline);
+	public void init_prompt (void);
+	public char * pr_expand (constant char *proto, int maxwidth);
+	public char * eq_message (void);
+	public char * pr_string (void);
+	public char * wait_message (void);
+	public void init_search (void);
+	public void repaint_hilite (int on);
+	public void clear_attn (void);
+	public void undo_search (void);
+struct hilite_tree;
+	public void clr_hlist (struct hilite_tree *anchor);
+	public void clr_hilite (void);
+	public void clr_filter (void);
+	public int is_filtered (POSITION pos);
+	public POSITION next_unfiltered (POSITION pos);
+	public POSITION prev_unfiltered (POSITION pos);
+	public int is_hilited (POSITION pos, POSITION epos, int nohide, int *p_matches);
+	public void chg_caseless (void);
+	public void chg_hilite (void);
+	public int search (int search_type, char *pattern, int n);
+	public void prep_hilite (POSITION spos, POSITION epos, int maxlines);
+	public void set_filter_pattern (char *pattern, int search_type);
+	public int is_filtering (void);
+	public RETSIGTYPE winch (int type);
+	public void init_signals (int on);
+	public void psignals (void);
+	public void cleantags (void);
+	public int gettagtype (void);
+	public void findtag (char *tag);
+	public POSITION tagsearch (void);
+	public char * nexttag (int n);
+	public char * prevtag (int n);
+	public int ntags (void);
+	public int curr_tag (void);
+	public int edit_tagfile (void);
+	public void open_getchr (void);
+	public void close_getchr (void);
+	public int getchr (void);
diff --git a/ifile.c b/ifile.c
index fea2ea1ea915..0d921558444c 100644
--- a/ifile.c
+++ b/ifile.c
@@ -49,9 +49,7 @@ static struct ifile anchor = { &anchor, &anchor, NULL, NULL, 0, 0, '\0',
 static int ifiles = 0;
 
 	static void
-incr_index(p, incr)
-	register struct ifile *p;
-	int incr;
+incr_index(struct ifile *p, int incr)
 {
 	for (;  p != &anchor;  p = p->h_next)
 		p->h_index += incr;
@@ -61,9 +59,7 @@ incr_index(p, incr)
  * Link an ifile into the ifile list.
  */
 	static void
-link_ifile(p, prev)
-	struct ifile *p;
-	struct ifile *prev;
+link_ifile(struct ifile *p, struct ifile *prev)
 {
 	/*
 	 * Link into list.
@@ -87,8 +83,7 @@ link_ifile(p, prev)
  * Unlink an ifile from the ifile list.
  */
 	static void
-unlink_ifile(p)
-	struct ifile *p;
+unlink_ifile(struct ifile *p)
 {
 	p->h_next->h_prev = p->h_prev;
 	p->h_prev->h_next = p->h_next;
@@ -103,11 +98,9 @@ unlink_ifile(p)
  * Return a pointer to the new ifile structure.
  */
 	static struct ifile *
-new_ifile(filename, prev)
-	char *filename;
-	struct ifile *prev;
+new_ifile(char *filename, struct ifile *prev)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	/*
 	 * Allocate and initialize structure.
@@ -126,10 +119,9 @@ new_ifile(filename, prev)
  * Delete an existing ifile structure.
  */
 	public void
-del_ifile(h)
-	IFILE h;
+del_ifile(IFILE h)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	if (h == NULL_IFILE)
 		return;
@@ -150,10 +142,9 @@ del_ifile(h)
  * Get the ifile after a given one in the list.
  */
 	public IFILE
-next_ifile(h)
-	IFILE h;
+next_ifile(IFILE h)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
 	if (p->h_next == &anchor)
@@ -165,10 +156,9 @@ next_ifile(h)
  * Get the ifile before a given one in the list.
  */
 	public IFILE
-prev_ifile(h)
-	IFILE h;
+prev_ifile(IFILE h)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	p = (h == NULL_IFILE) ? &anchor : int_ifile(h);
 	if (p->h_prev == &anchor)
@@ -180,8 +170,7 @@ prev_ifile(h)
  * Return a different ifile from the given one.
  */
 	public IFILE
-getoff_ifile(ifile)
-	IFILE ifile;
+getoff_ifile(IFILE ifile)
 {
 	IFILE newifile;
 	
@@ -196,7 +185,7 @@ getoff_ifile(ifile)
  * Return the number of ifiles.
  */
 	public int
-nifile()
+nifile(void)
 {
 	return (ifiles);
 }
@@ -205,10 +194,9 @@ nifile()
  * Find an ifile structure, given a filename.
  */
 	static struct ifile *
-find_ifile(filename)
-	char *filename;
+find_ifile(char *filename)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	for (p = anchor.h_next;  p != &anchor;  p = p->h_next)
 		if (strcmp(filename, p->h_filename) == 0)
@@ -222,11 +210,9 @@ find_ifile(filename)
  * insert the new ifile after "prev" in the list.
  */
 	public IFILE
-get_ifile(filename, prev)
-	char *filename;
-	IFILE prev;
+get_ifile(char *filename, IFILE prev)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	if ((p = find_ifile(filename)) == NULL)
 		p = new_ifile(filename, int_ifile(prev));
@@ -237,8 +223,7 @@ get_ifile(filename, prev)
  * Get the filename associated with a ifile.
  */
 	public char *
-get_filename(ifile)
-	IFILE ifile;
+get_filename(IFILE ifile)
 {
 	if (ifile == NULL)
 		return (NULL);
@@ -249,8 +234,7 @@ get_filename(ifile)
  * Get the index of the file associated with a ifile.
  */
 	public int
-get_index(ifile)
-	IFILE ifile;
+get_index(IFILE ifile)
 {
 	return (int_ifile(ifile)->h_index); 
 }
@@ -259,9 +243,7 @@ get_index(ifile)
  * Save the file position to be associated with a given file.
  */
 	public void
-store_pos(ifile, scrpos)
-	IFILE ifile;
-	struct scrpos *scrpos;
+store_pos(IFILE ifile, struct scrpos *scrpos)
 {
 	int_ifile(ifile)->h_scrpos = *scrpos;
 }
@@ -271,9 +253,7 @@ store_pos(ifile, scrpos)
  * If no position has been associated with the file, return NULL_POSITION.
  */
 	public void
-get_pos(ifile, scrpos)
-	IFILE ifile;
-	struct scrpos *scrpos;
+get_pos(IFILE ifile, struct scrpos *scrpos)
 {
 	*scrpos = int_ifile(ifile)->h_scrpos;
 }
@@ -282,8 +262,7 @@ get_pos(ifile, scrpos)
  * Mark the ifile as "opened".
  */
 	public void
-set_open(ifile)
-	IFILE ifile;
+set_open(IFILE ifile)
 {
 	int_ifile(ifile)->h_opened = 1;
 }
@@ -292,47 +271,40 @@ set_open(ifile)
  * Return whether the ifile has been opened previously.
  */
 	public int
-opened(ifile)
-	IFILE ifile;
+opened(IFILE ifile)
 {
 	return (int_ifile(ifile)->h_opened);
 }
 
 	public void
-hold_ifile(ifile, incr)
-	IFILE ifile;
-	int incr;
+hold_ifile(IFILE ifile, int incr)
 {
 	int_ifile(ifile)->h_hold += incr;
 }
 
 	public int
-held_ifile(ifile)
-	IFILE ifile;
+held_ifile(IFILE ifile)
 {
 	return (int_ifile(ifile)->h_hold);
 }
 
 	public void *
-get_filestate(ifile)
-	IFILE ifile;
+get_filestate(IFILE ifile)
 {
 	return (int_ifile(ifile)->h_filestate);
 }
 
 	public void
-set_filestate(ifile, filestate)
-	IFILE ifile;
-	void *filestate;
+set_filestate(IFILE ifile, void *filestate)
 {
 	int_ifile(ifile)->h_filestate = filestate;
 }
 
 #if 0
 	public void
-if_dump()
+if_dump(void)
 {
-	register struct ifile *p;
+	struct ifile *p;
 
 	for (p = anchor.h_next;  p != &anchor;  p = p->h_next)
 	{
diff --git a/input.c b/input.c
index 9419a02711b5..b9e5de931b1b 100644
--- a/input.c
+++ b/input.c
@@ -42,12 +42,11 @@ extern int size_linebuf;
  * of the NEXT line.  The line obtained is the line starting at curr_pos.
  */
 	public POSITION
-forw_line(curr_pos)
-	POSITION curr_pos;
+forw_line(POSITION curr_pos)
 {
 	POSITION base_pos;
 	POSITION new_pos;
-	register int c;
+	int c;
 	int blankline;
 	int endline;
 	int backchars;
@@ -249,8 +248,7 @@ get_forw_line:
  * of the PREVIOUS line.  The line obtained is the one starting at new_pos.
  */
 	public POSITION
-back_line(curr_pos)
-	POSITION curr_pos;
+back_line(POSITION curr_pos)
 {
 	POSITION new_pos, begin_new_pos, base_pos;
 	int c;
@@ -429,8 +427,7 @@ get_back_line:
  * Set attnpos.
  */
 	public void
-set_attnpos(pos)
-	POSITION pos;
+set_attnpos(POSITION pos)
 {
 	int c;
 
diff --git a/jump.c b/jump.c
index 8373d8b54970..16bd22d58036 100644
--- a/jump.c
+++ b/jump.c
@@ -26,7 +26,7 @@ extern int top_scroll;
  * Jump to the end of the file.
  */
 	public void
-jump_forw()
+jump_forw(void)
 {
 	POSITION pos;
 	POSITION end_pos;
@@ -64,7 +64,7 @@ jump_forw()
  * Jump to the last buffered line in the file.
  */
 	public void
-jump_forw_buffered()
+jump_forw_buffered(void)
 {
 	POSITION end;
 
@@ -82,8 +82,7 @@ jump_forw_buffered()
  * Jump to line n in the file.
  */
 	public void
-jump_back(linenum)
-	LINENUM linenum;
+jump_back(LINENUM linenum)
 {
 	POSITION pos;
 	PARG parg;
@@ -115,7 +114,7 @@ jump_back(linenum)
  * Repaint the screen.
  */
 	public void
-repaint()
+repaint(void)
 {
 	struct scrpos scrpos;
 	/*
@@ -131,9 +130,7 @@ repaint()
  * Jump to a specified percentage into the file.
  */
 	public void
-jump_percent(percent, fraction)
-	int percent;
-	long fraction;
+jump_percent(int percent, long fraction)
 {
 	POSITION pos, len;
 
@@ -164,9 +161,7 @@ jump_percent(percent, fraction)
  * the first character in a line.
  */
 	public void
-jump_line_loc(pos, sline)
-	POSITION pos;
-	int sline;
+jump_line_loc(POSITION pos, int sline)
 {
 	int c;
 
@@ -192,11 +187,9 @@ jump_line_loc(pos, sline)
  * Place the target line on a specified line on the screen.
  */
 	public void
-jump_loc(pos, sline)
-	POSITION pos;
-	int sline;
+jump_loc(POSITION pos, int sline)
 {
-	register int nline;
+	int nline;
 	POSITION tpos;
 	POSITION bpos;
 
diff --git a/less.h b/less.h
index f57fb1ecf061..4123c352d258 100644
--- a/less.h
+++ b/less.h
@@ -528,6 +528,6 @@ struct wchar_range_table
 #include "funcs.h"
 
 /* Functions not included in funcs.h */
-void postoa();
-void linenumtoa();
-void inttoa();
+void postoa(POSITION num, char *buf);
+void linenumtoa(LINENUM num, char *buf);
+void inttoa(int num, char *buf);
diff --git a/lessecho.c b/lessecho.c
index fb0b22ddc000..e4a23f5f39c5 100644
--- a/lessecho.c
+++ b/lessecho.c
@@ -38,14 +38,14 @@ static char metachars[64] = "";
 static int num_metachars = 0;
 
 	static void
-pr_usage()
+pr_usage(void)
 {
 	fprintf(stderr,
 		"usage: lessecho [-ox] [-cx] [-pn] [-dn] [-mx] [-nn] [-ex] [-fn] [-a] file ...\n");
 }
 
 	static void
-pr_version()
+pr_version(void)
 {
 	char *p;
 	char buf[10];
@@ -61,18 +61,14 @@ pr_version()
 }
 
 	static void
-pr_error(s)
-	char *s;
+pr_error(char *s)
 {
 	fprintf(stderr, "%s\n", s);
 	exit(1);
 }
 
 	static long
-lstrtol(s, radix, pend)
-	char *s;
-	int radix;
-	char **pend;
+lstrtol(char *s, int radix, char **pend)
 {
 	int v;
 	int neg = 0;
diff --git a/lesskey.c b/lesskey.c
index 298748b9a04a..47b765424fbc 100644
--- a/lesskey.c
+++ b/lesskey.c
@@ -213,19 +213,19 @@ char *outfile = NULL ;
 int linenum;
 int errors;
 
+static void lk_error(char *s);
+
 extern char version[];
 
 	void
-usage()
+usage(void)
 {
 	fprintf(stderr, "usage: lesskey [-o output] [input]\n");
 	exit(1);
 }
 
 	char *
-mkpathname(dirname, filename)
-	char *dirname;
-	char *filename;
+mkpathname(char *dirname, char *filename)
 {
 	char *pathname;
 
@@ -240,8 +240,7 @@ mkpathname(dirname, filename)
  * Figure out the name of a default file (in the user's HOME directory).
  */
 	char *
-homefile(filename)
-	char *filename;
+homefile(char *filename)
 {
 	char *p;
 	char *pathname;
@@ -264,9 +263,7 @@ homefile(filename)
  * Parse command line arguments.
  */
 	void
-parse_args(argc, argv)
-	int argc;
-	char **argv;
+parse_args(int argc, char **argv)
 {
 	char *arg;
 
@@ -339,7 +336,7 @@ parse_args(argc, argv)
  * Initialize data structures.
  */
 	void
-init_tables()
+init_tables(void)
 {
 	cmdtable.names = cmdnames;
 	cmdtable.pbuffer = cmdtable.buffer;
@@ -355,13 +352,11 @@ init_tables()
  * Parse one character of a string.
  */
 	char *
-tstr(pp, xlate)
-	char **pp;
-	int xlate;
+tstr(char **pp, int xlate)
 {
-	register char *p;
-	register char ch;
-	register int i;
+	char *p;
+	char ch;
+	int i;
 	static char buf[10];
 	static char tstr_control_k[] =
 		{ SK_SPECIAL_KEY, SK_CONTROL_K, 6, 1, 1, 1, '\0' };
@@ -421,7 +416,7 @@ tstr(pp, xlate)
 				case 'e': ch = SK_END; break;
 				case 'x': ch = SK_DELETE; break;
 				default:
-					error("illegal char after \\k");
+					lk_error("illegal char after \\k");
 					*pp = p+1;
 					return ("");
 				}
@@ -471,8 +466,7 @@ tstr(pp, xlate)
  * Skip leading spaces in a string.
  */
 	public char *
-skipsp(s)
-	register char *s;
+skipsp(char *s)
 {
 	while (*s == ' ' || *s == '\t')	
 		s++;
@@ -483,8 +477,7 @@ skipsp(s)
  * Skip non-space characters in a string.
  */
 	public char *
-skipnsp(s)
-	register char *s;
+skipnsp(char *s)
 {
 	while (*s != '\0' && *s != ' ' && *s != '\t')
 		s++;
@@ -496,10 +489,9 @@ skipnsp(s)
  * strip off the trailing newline & any trailing # comment.
  */
 	char *
-clean_line(s)
-	char *s;
+clean_line(char *s)
 {
-	register int i;
+	int i;
 
 	s = skipsp(s);
 	for (i = 0;  s[i] != '\n' && s[i] != '\r' && s[i] != '\0';  i++)
@@ -513,12 +505,11 @@ clean_line(s)
  * Add a byte to the output command table.
  */
 	void
-add_cmd_char(c)
-	int c;
+add_cmd_char(int c)
 {
 	if (currtable->pbuffer >= currtable->buffer + MAX_USERCMD)
 	{
-		error("too many commands");
+		lk_error("too many commands");
 		exit(1);
 	}
 	*(currtable->pbuffer)++ = c;
@@ -528,8 +519,7 @@ add_cmd_char(c)
  * Add a string to the output command table.
  */
 	void
-add_cmd_str(s)
-	char *s;
+add_cmd_str(char *s)
 {
 	for ( ;  *s != '\0';  s++)
 		add_cmd_char(*s);
@@ -539,8 +529,7 @@ add_cmd_str(s)
  * See if we have a special "control" line.
  */
 	int
-control_line(s)
-	char *s;
+control_line(char *s)
 {
 #define	PREFIX(str,pat)	(strncmp(str,pat,strlen(pat)) == 0)
 
@@ -572,10 +561,7 @@ control_line(s)
  * Output some bytes.
  */
 	void
-fputbytes(fd, buf, len)
-	FILE *fd;
-	char *buf;
-	int len;
+fputbytes(FILE *fd, char *buf, int len)
 {
 	while (len-- > 0)
 	{
@@ -588,9 +574,7 @@ fputbytes(fd, buf, len)
  * Output an integer, in special KRADIX form.
  */
 	void
-fputint(fd, val)
-	FILE *fd;
-	unsigned int val;
+fputint(FILE *fd, unsigned int val)
 {
 	char c;
 
@@ -610,21 +594,19 @@ fputint(fd, val)
  * Find an action, given the name of the action.
  */
 	int
-findaction(actname)
-	char *actname;
+findaction(char *actname)
 {
 	int i;
 
 	for (i = 0;  currtable->names[i].cn_name != NULL;  i++)
 		if (strcmp(currtable->names[i].cn_name, actname) == 0)
 			return (currtable->names[i].cn_action);
-	error("unknown action");
+	lk_error("unknown action");
 	return (A_INVALID);
 }
 
-	void
-error(s)
-	char *s;
+	static void
+lk_error(char *s)
 {
 	fprintf(stderr, "line %d: %s\n", linenum, s);
 	errors++;
@@ -632,8 +614,7 @@ error(s)
 
 
 	void
-parse_cmdline(p)
-	char *p;
+parse_cmdline(char *p)
 {
 	int cmdlen;
 	char *actname;
@@ -650,7 +631,7 @@ parse_cmdline(p)
 		s = tstr(&p, 1);
 		cmdlen += (int) strlen(s);
 		if (cmdlen > MAX_CMDLEN)
-			error("command too long");
+			lk_error("command too long");
 		else
 			add_cmd_str(s);
 	} while (*p != ' ' && *p != '\t' && *p != '\0');
@@ -667,7 +648,7 @@ parse_cmdline(p)
 	p = skipsp(p);
 	if (*p == '\0')
 	{
-		error("missing action");
+		lk_error("missing action");
 		return;
 	}
 	actname = p;
@@ -702,8 +683,7 @@ parse_cmdline(p)
 }
 
 	void
-parse_varline(p)
-	char *p;
+parse_varline(char *p)
 {
 	char *s;
 
@@ -720,7 +700,7 @@ parse_varline(p)
 	p = skipsp(p);
 	if (*p++ != '=')
 	{
-		error("missing =");
+		lk_error("missing =");
 		return;
 	}
 
@@ -739,8 +719,7 @@ parse_varline(p)
  * Parse a line from the lesskey file.
  */
 	void
-parse_line(line)
-	char *line;
+parse_line(char *line)
 {
 	char *p;
 
@@ -765,9 +744,7 @@ parse_line(line)
 }
 
 	int
-main(argc, argv)
-	int argc;
-	char *argv[];
+main(int argc, char *argv[])
 {
 	FILE *desc;
 	FILE *out;
diff --git a/line.c b/line.c
index e54835d4744b..464afda3b885 100644
--- a/line.c
+++ b/line.c
@@ -40,9 +40,9 @@ static POSITION pendpos;
 static char *end_ansi_chars;
 static char *mid_ansi_chars;
 
-static int attr_swidth();
-static int attr_ewidth();
-static int do_append();
+static int attr_swidth(int);
+static int attr_ewidth(int);
+static int do_append(LWCHAR, char *, POSITION);
 
 extern int sigs;
 extern int bs_mode;
@@ -70,7 +70,7 @@ static POSITION mbc_pos;
  * Initialize from environment variables.
  */
 	public void
-init_line()
+init_line(void)
 {
 	end_ansi_chars = lgetenv("LESSANSIENDCHARS");
 	if (end_ansi_chars == NULL || *end_ansi_chars == '\0')
@@ -89,7 +89,7 @@ init_line()
  * Expand the line buffer.
  */
 	static int
-expand_linebuf()
+expand_linebuf(void)
 {
 	/* Double the size of the line buffer. */
 	int new_size = size_linebuf * 2;
@@ -137,8 +137,7 @@ expand_linebuf()
  * Is a character ASCII?
  */
 	public int
-is_ascii_char(ch)
-	LWCHAR ch;
+is_ascii_char(LWCHAR ch)
 {
 	return (ch <= 0x7F);
 }
@@ -147,7 +146,7 @@ is_ascii_char(ch)
  * Rewind the line buffer.
  */
 	public void
-prewind()
+prewind(void)
 {
 	curr = 0;
 	column = 0;
@@ -166,11 +165,10 @@ prewind()
  * Insert the line number (of the given position) into the line buffer.
  */
 	public void
-plinenum(pos)
-	POSITION pos;
+plinenum(POSITION pos)
 {
-	register LINENUM linenum = 0;
-	register int i;
+	LINENUM linenum = 0;
+	int i;
 
 	if (linenums == OPT_ONPLUS)
 	{
@@ -237,8 +235,7 @@ plinenum(pos)
  * This means discarding N printable chars at the start of the buffer.
  */
 	static void
-pshift(shift)
-	int shift;
+pshift(int shift)
 {
 	LWCHAR prev_ch = 0;
 	unsigned char c;
@@ -355,7 +352,7 @@ pshift(shift)
  *
  */
 	public void
-pshift_all()
+pshift_all(void)
 {
 	pshift(column);
 }
@@ -365,8 +362,7 @@ pshift_all()
  * for a given character attribute.
  */
 	static int
-attr_swidth(a)
-	int a;
+attr_swidth(int a)
 {
 	int w = 0;
 
@@ -389,8 +385,7 @@ attr_swidth(a)
  * for a given character attribute.
  */
 	static int
-attr_ewidth(a)
-	int a;
+attr_ewidth(int a)
 {
 	int w = 0;
 
@@ -415,10 +410,7 @@ attr_ewidth(a)
  * attribute sequence to be inserted, so this must be taken into account.
  */
 	static int
-pwidth(ch, a, prev_ch)
-	LWCHAR ch;
-	int a;
-	LWCHAR prev_ch;
+pwidth(LWCHAR ch, int a, LWCHAR prev_ch)
 {
 	int w;
 
@@ -479,10 +471,10 @@ pwidth(ch, a, prev_ch)
  * Return 1 if one is found.
  */
 	static int
-backc()
+backc(void)
 {
 	LWCHAR prev_ch;
-	char *p = linebuf + curr;
+	constant char *p = linebuf + curr;
 	LWCHAR ch = step_char(&p, -1, linebuf + lmargin);
 	int width;
 
@@ -507,9 +499,9 @@ backc()
  * Are we currently within a recognized ANSI escape sequence?
  */
 	static int
-in_ansi_esc_seq()
+in_ansi_esc_seq(void)
 {
-	char *p;
+	constant char *p;
 
 	/*
 	 * Search backwards for either an ESC (which means we ARE in a seq);
@@ -530,8 +522,7 @@ in_ansi_esc_seq()
  * Is a character the end of an ANSI escape sequence?
  */
 	public int
-is_ansi_end(ch)
-	LWCHAR ch;
+is_ansi_end(LWCHAR ch)
 {
 	if (!is_ascii_char(ch))
 		return (0);
@@ -542,8 +533,7 @@ is_ansi_end(ch)
  *
  */
 	public int
-is_ansi_middle(ch)
-	LWCHAR ch;
+is_ansi_middle(LWCHAR ch)
 {
 	if (!is_ascii_char(ch))
 		return (0);
@@ -561,11 +551,7 @@ is_ansi_middle(ch)
 	} while (0)
 
 	static int
-store_char(ch, a, rep, pos)
-	LWCHAR ch;
-	int a;
-	char *rep;
-	POSITION pos;
+store_char(LWCHAR ch, int a, char *rep, POSITION pos)
 {
 	int w;
 	int replen;
@@ -599,7 +585,7 @@ store_char(ch, a, rep, pos)
 	{
 		if (!is_ansi_end(ch) && !is_ansi_middle(ch)) {
 			/* Remove whole unrecognized sequence.  */
-			char *p = &linebuf[curr];
+			constant char *p = &linebuf[curr];
 			LWCHAR bch;
 			do {
 				bch = step_char(&p, -1, linebuf);
@@ -617,7 +603,7 @@ store_char(ch, a, rep, pos)
 	}
 	else
 	{
-		char *p = &linebuf[curr];
+		constant char *p = &linebuf[curr];
 		LWCHAR prev_ch = step_char(&p, -1, linebuf);
 		w = pwidth(ch, a, prev_ch);
 	}
@@ -665,9 +651,7 @@ store_char(ch, a, rep, pos)
 	do { if (store_tab((a),(pos))) return (1); } while (0)
 
 	static int
-store_tab(attr, pos)
-	int attr;
-	POSITION pos;
+store_tab(int attr, POSITION pos)
 {
 	int to_tab = column + cshift - lmargin;
 	int i;
@@ -696,9 +680,7 @@ store_tab(attr, pos)
 	do { if (store_prchar((c), (pos))) return 1; } while (0)
 
 	static int
-store_prchar(c, pos)
-	LWCHAR c;
-	POSITION pos;
+store_prchar(LWCHAR c, POSITION pos)
 {
 	char *s;
 
@@ -722,8 +704,7 @@ store_prchar(c, pos)
 }
 
 	static int
-flush_mbc_buf(pos)
-	POSITION pos;
+flush_mbc_buf(POSITION pos)
 {
 	int i;
 
@@ -740,9 +721,7 @@ flush_mbc_buf(pos)
  * Returns 0 if ok, 1 if couldn't fit in buffer.
  */
 	public int
-pappend(c, pos)
-	unsigned char c;
-	POSITION pos;
+pappend(unsigned char c, POSITION pos)
 {
 	int r;
 
@@ -845,12 +824,9 @@ pappend(c, pos)
 }
 
 	static int
-do_append(ch, rep, pos)
-	LWCHAR ch;
-	char *rep;
-	POSITION pos;
+do_append(LWCHAR ch, char *rep, POSITION pos)
 {
-	register int a;
+	int a;
 	LWCHAR prev_ch;
 
 	a = AT_NORMAL;
@@ -985,7 +961,7 @@ do_append(ch, rep, pos)
  *
  */
 	public int
-pflushmbc()
+pflushmbc(void)
 {
 	int r = 0;
 
@@ -1002,9 +978,7 @@ pflushmbc()
  * Terminate the line in the line buffer.
  */
 	public void
-pdone(endline, forw)
-	int endline;
-	int forw;
+pdone(int endline, int forw)
 {
 	(void) pflushmbc();
 
@@ -1081,8 +1055,7 @@ pdone(endline, forw)
  *
  */
 	public void
-set_status_col(c)
-	char c;
+set_status_col(char c)
 {
 	linebuf[0] = c;
 	attr[0] = AT_NORMAL|AT_HILITE;
@@ -1094,9 +1067,7 @@ set_status_col(c)
  * and the character attribute in *ap.
  */
 	public int
-gline(i, ap)
-	register int i;
-	register int *ap;
+gline(int i, int *ap)
 {
 	if (is_null_line)
 	{
@@ -1126,7 +1097,7 @@ gline(i, ap)
  * Indicate that there is no current line.
  */
 	public void
-null_line()
+null_line(void)
 {
 	is_null_line = 1;
 	cshift = 0;
@@ -1138,13 +1109,10 @@ null_line()
  * {{ This is supposed to be more efficient than forw_line(). }}
  */
 	public POSITION
-forw_raw_line(curr_pos, linep, line_lenp)
-	POSITION curr_pos;
-	char **linep;
-	int *line_lenp;
+forw_raw_line(POSITION curr_pos, char **linep, int *line_lenp)
 {
-	register int n;
-	register int c;
+	int n;
+	int c;
 	POSITION new_pos;
 
 	if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
@@ -1187,13 +1155,10 @@ forw_raw_line(curr_pos, linep, line_lenp)
  * {{ This is supposed to be more efficient than back_line(). }}
  */
 	public POSITION
-back_raw_line(curr_pos, linep, line_lenp)
-	POSITION curr_pos;
-	char **linep;
-	int *line_lenp;
+back_raw_line(POSITION curr_pos, char **linep, int *line_lenp)
 {
-	register int n;
-	register int c;
+	int n;
+	int c;
 	POSITION new_pos;
 
 	if (curr_pos == NULL_POSITION || curr_pos <= ch_zero() ||
diff --git a/linenum.c b/linenum.c
index 6d078ec86969..776db34352c5 100644
--- a/linenum.c
+++ b/linenum.c
@@ -73,9 +73,9 @@ extern int screen_trashed;
  * Initialize the line number structures.
  */
 	public void
-clr_linenum()
+clr_linenum(void)
 {
-	register struct linenum_info *p;
+	struct linenum_info *p;
 
 	/*
 	 * Put all the entries on the free list.
@@ -101,8 +101,7 @@ clr_linenum()
  * Calculate the gap for an entry.
  */
 	static void
-calcgap(p)
-	register struct linenum_info *p;
+calcgap(struct linenum_info *p)
 {
 	/*
 	 * Don't bother to compute a gap for the anchor.
@@ -121,15 +120,13 @@ calcgap(p)
  * FIRST character in the specified line.
  */
 	public void
-add_lnum(linenum, pos)
-	LINENUM linenum;
-	POSITION pos;
+add_lnum(LINENUM linenum, POSITION pos)
 {
-	register struct linenum_info *p;
-	register struct linenum_info *new;
-	register struct linenum_info *nextp;
-	register struct linenum_info *prevp;
-	register POSITION mingap;
+	struct linenum_info *p;
+	struct linenum_info *new;
+	struct linenum_info *nextp;
+	struct linenum_info *prevp;
+	POSITION mingap;
 
 	/*
 	 * Find the proper place in the list for the new one.
@@ -209,7 +206,7 @@ add_lnum(linenum, pos)
  * line number, print a message to tell the user what we're doing.
  */
 	static void
-longloopmessage()
+longloopmessage(void)
 {
 	ierror("Calculating line numbers", NULL_PARG);
 }
@@ -220,7 +217,7 @@ static time_type startime;
 #endif
 
 	static void
-longish()
+longish(void)
 {
 #if HAVE_TIME
 	if (loopcount >= 0 && ++loopcount > 100)
@@ -246,7 +243,7 @@ longish()
  * a lengthy line number calculation.
  */
 	static void
-abort_long()
+abort_long(void)
 {
 	if (linenums == OPT_ONPLUS)
 		/*
@@ -262,11 +259,10 @@ abort_long()
  * Return 0 if we can't figure it out.
  */
 	public LINENUM
-find_linenum(pos)
-	POSITION pos;
+find_linenum(POSITION pos)
 {
-	register struct linenum_info *p;
-	register LINENUM linenum;
+	struct linenum_info *p;
+	LINENUM linenum;
 	POSITION cpos;
 
 	if (!linenums)
@@ -377,10 +373,9 @@ find_linenum(pos)
  * Return NULL_POSITION if we can't figure it out.
  */
 	public POSITION
-find_pos(linenum)
-	LINENUM linenum;
+find_pos(LINENUM linenum)
 {
-	register struct linenum_info *p;
+	struct linenum_info *p;
 	POSITION cpos;
 	LINENUM clinenum;
 
@@ -450,8 +445,7 @@ find_pos(linenum)
  * the "current" line (e.g. TOP, BOTTOM, MIDDLE, etc).
  */
 	public LINENUM
-currline(where)
-	int where;
+currline(int where)
 {
 	POSITION pos;
 	POSITION len;
diff --git a/lsystem.c b/lsystem.c
index 8a7cb8f2a971..93a5e03ae590 100644
--- a/lsystem.c
+++ b/lsystem.c
@@ -38,14 +38,12 @@ extern IFILE curr_ifile;
  * Like plain "system()", but handles resetting terminal modes, etc.
  */
 	public void
-lsystem(cmd, donemsg)
-	char *cmd;
-	char *donemsg;
+lsystem(char *cmd, char *donemsg)
 {
-	register int inp;
+	int inp;
 #if HAVE_SHELL
-	register char *shell;
-	register char *p;
+	char *shell;
+	char *p;
 #endif
 	IFILE save_ifile;
 #if MSDOS_COMPILER && MSDOS_COMPILER!=WIN32C
@@ -250,9 +248,7 @@ lsystem(cmd, donemsg)
  * the whole current screen is piped.
  */
 	public int
-pipe_mark(c, cmd)
-	int c;
-	char *cmd;
+pipe_mark(int c, char *cmd)
 {
 	POSITION mpos, tpos, bpos;
 
@@ -284,13 +280,10 @@ pipe_mark(c, cmd)
  * Feed it the file contents between the positions spos and epos.
  */
 	public int
-pipe_data(cmd, spos, epos)
-	char *cmd;
-	POSITION spos;
-	POSITION epos;
+pipe_data(char *cmd, POSITION spos, POSITION epos)
 {
-	register FILE *f;
-	register int c;
+	FILE *f;
+	int c;
 	extern FILE *popen();
 
 	/*
diff --git a/main.c b/main.c
index 149999cd4b53..9f5488054b15 100644
--- a/main.c
+++ b/main.c
@@ -291,10 +291,9 @@ main(argc, argv)
  * (that is, to a buffer allocated by calloc).
  */
 	public char *
-save(s)
-	char *s;
+save(constant char *s)
 {
-	register char *p;
+	char *p;
 
 	p = (char *) ecalloc(strlen(s)+1, sizeof(char));
 	strcpy(p, s);
@@ -306,11 +305,9 @@ save(s)
  * Like calloc(), but never returns an error (NULL).
  */
 	public VOID_POINTER
-ecalloc(count, size)
-	int count;
-	unsigned int size;
+ecalloc(int count, unsigned int size)
 {
-	register VOID_POINTER p;
+	VOID_POINTER p;
 
 	p = (VOID_POINTER) calloc(count, size);
 	if (p != NULL)
@@ -325,8 +322,7 @@ ecalloc(count, size)
  * Skip leading spaces in a string.
  */
 	public char *
-skipsp(s)
-	register char *s;
+skipsp(char *s)
 {
 	while (*s == ' ' || *s == '\t')	
 		s++;
@@ -339,14 +335,11 @@ skipsp(s)
  * character; the remainder of the first string may be either case.
  */
 	public int
-sprefix(ps, s, uppercase)
-	char *ps;
-	char *s;
-	int uppercase;
+sprefix(char *ps, char *s, int uppercase)
 {
-	register int c;
-	register int sc;
-	register int len = 0;
+	int c;
+	int sc;
+	int len = 0;
 
 	for ( ;  *s != '\0';  s++, ps++)
 	{
@@ -372,8 +365,7 @@ sprefix(ps, s, uppercase)
  * Exit the program.
  */
 	public void
-quit(status)
-	int status;
+quit(int status)
 {
 	static int save_status;
 
diff --git a/mark.c b/mark.c
index 44d606fc9d2e..59eda4b2d56e 100644
--- a/mark.c
+++ b/mark.c
@@ -27,7 +27,7 @@ static struct mark marks[NMARKS];
  * Initialize the mark table to show no marks are set.
  */
 	public void
-init_mark()
+init_mark(void)
 {
 	int i;
 
@@ -39,8 +39,7 @@ init_mark()
  * See if a mark letter is valid (between a and z).
  */
 	static struct mark *
-getumark(c)
-	int c;
+getumark(int c)
 {
 	if (c >= 'a' && c <= 'z')
 		return (&marks[c-'a']);
@@ -58,10 +57,9 @@ getumark(c)
  * or may be constructed on the fly for certain characters like ^, $.
  */
 	static struct mark *
-getmark(c)
-	int c;
+getmark(int c)
 {
-	register struct mark *m;
+	struct mark *m;
 	static struct mark sm;
 
 	switch (c)
@@ -124,8 +122,7 @@ getmark(c)
  * Is a mark letter is invalid?
  */
 	public int
-badmark(c)
-	int c;
+badmark(int c)
 {
 	return (getmark(c) == NULL);
 }
@@ -134,10 +131,9 @@ badmark(c)
  * Set a user-defined mark.
  */
 	public void
-setmark(c)
-	int c;
+setmark(int c)
 {
-	register struct mark *m;
+	struct mark *m;
 	struct scrpos scrpos;
 
 	m = getumark(c);
@@ -152,7 +148,7 @@ setmark(c)
  * Set lmark (the mark named by the apostrophe).
  */
 	public void
-lastmark()
+lastmark(void)
 {
 	struct scrpos scrpos;
 
@@ -169,10 +165,9 @@ lastmark()
  * Go to a mark.
  */
 	public void
-gomark(c)
-	int c;
+gomark(int c)
 {
-	register struct mark *m;
+	struct mark *m;
 	struct scrpos scrpos;
 
 	m = getmark(c);
@@ -217,10 +212,9 @@ gomark(c)
  * because it's always the first non-blank line on the screen.
  */
 	public POSITION
-markpos(c)
-	int c;
+markpos(int c)
 {
-	register struct mark *m;
+	struct mark *m;
 
 	m = getmark(c);
 	if (m == NULL)
@@ -238,8 +232,7 @@ markpos(c)
  * Clear the marks associated with a specified ifile.
  */
 	public void
-unmark(ifile)
-	IFILE ifile;
+unmark(IFILE ifile)
 {
 	int i;
 
diff --git a/mkhelp.c b/mkhelp.c
index d4e406337f96..bc66e7d5ff1d 100644
--- a/mkhelp.c
+++ b/mkhelp.c
@@ -18,9 +18,7 @@
 #include <stdio.h>
 
 	int
-main(argc, argv)
-	int argc;
-	char *argv[];
+main(int argc, char *argv[])
 {
 	int ch;
 	int prevch;
diff --git a/optfunc.c b/optfunc.c
index c3bb6b2d9eb1..20ff1ea4cc04 100644
--- a/optfunc.c
+++ b/optfunc.c
@@ -75,9 +75,7 @@ extern int bl_fg_color, bl_bg_color;
  * Handler for -o option.
  */
 	public void
-opt_o(type, s)
-	int type;
-	char *s;
+opt_o(int type, char *s)
 {
 	PARG parg;
 
@@ -125,9 +123,7 @@ opt_o(type, s)
  * Handler for -O option.
  */
 	public void
-opt__O(type, s)
-	int type;
-	char *s;
+opt__O(int type, char *s)
 {
 	force_logfile = TRUE;
 	opt_o(type, s);
@@ -138,9 +134,7 @@ opt__O(type, s)
  * Handlers for -j option.
  */
 	public void
-opt_j(type, s)
-	int type;
-	char *s;
+opt_j(int type, char *s)
 {
 	PARG parg;
 	char buf[16];
@@ -192,7 +186,7 @@ opt_j(type, s)
 }
 
 	public void
-calc_jump_sline()
+calc_jump_sline(void)
 {
 	if (jump_sline_fraction < 0)
 		return;
@@ -203,9 +197,7 @@ calc_jump_sline()
  * Handlers for -# option.
  */
 	public void
-opt_shift(type, s)
-	int type;
-	char *s;
+opt_shift(int type, char *s)
 {
 	PARG parg;
 	char buf[16];
@@ -256,7 +248,7 @@ opt_shift(type, s)
 	}
 }
 	public void
-calc_shift_count()
+calc_shift_count(void)
 {
 	if (shift_count_fraction < 0)
 		return;
@@ -265,9 +257,7 @@ calc_shift_count()
 
 #if USERFILE
 	public void
-opt_k(type, s)
-	int type;
-	char *s;
+opt_k(int type, char *s)
 {
 	PARG parg;
 
@@ -289,9 +279,7 @@ opt_k(type, s)
  * Handler for -t option.
  */
 	public void
-opt_t(type, s)
-	int type;
-	char *s;
+opt_t(int type, char *s)
 {
 	IFILE save_ifile;
 	POSITION pos;
@@ -330,9 +318,7 @@ opt_t(type, s)
  * Handler for -T option.
  */
 	public void
-opt__T(type, s)
-	int type;
-	char *s;
+opt__T(int type, char *s)
 {
 	PARG parg;
 
@@ -359,9 +345,7 @@ opt__T(type, s)
  * Handler for -p option.
  */
 	public void
-opt_p(type, s)
-	int type;
-	register char *s;
+opt_p(int type, char *s)
 {
 	switch (type)
 	{
@@ -395,11 +379,9 @@ opt_p(type, s)
  * Handler for -P option.
  */
 	public void
-opt__P(type, s)
-	int type;
-	register char *s;
+opt__P(int type, char *s)
 {
-	register char **proto;
+	char **proto;
 	PARG parg;
 
 	switch (type)
@@ -434,9 +416,7 @@ opt__P(type, s)
  */
 	/*ARGSUSED*/
 	public void
-opt_b(type, s)
-	int type;
-	char *s;
+opt_b(int type, char *s)
 {
 	switch (type)
 	{
@@ -457,9 +437,7 @@ opt_b(type, s)
  */
 	/*ARGSUSED*/
 	public void
-opt_i(type, s)
-	int type;
-	char *s;
+opt_i(int type, char *s)
 {
 	switch (type)
 	{
@@ -477,9 +455,7 @@ opt_i(type, s)
  */
 	/*ARGSUSED*/
 	public void
-opt__V(type, s)
-	int type;
-	char *s;
+opt__V(int type, char *s)
 {
 	switch (type)
 	{
@@ -532,10 +508,7 @@ opt__V(type, s)
  * Parse an MSDOS color descriptor.
  */
    	static void
-colordesc(s, fg_color, bg_color)
-	char *s;
-	int *fg_color;
-	int *bg_color;
+colordesc(char *s, int *fg_color, int *bg_color)
 {
 	int fg, bg;
 	int err;
@@ -569,9 +542,7 @@ colordesc(s, fg_color, bg_color)
  */
 	/*ARGSUSED*/
 	public void
-opt_D(type, s)
-	int type;
-	char *s;
+opt_D(int type, char *s)
 {
 	switch (type)
 	{
@@ -614,9 +585,7 @@ opt_D(type, s)
  * Handler for the -x option.
  */
 	public void
-opt_x(type, s)
-	int type;
-	register char *s;
+opt_x(int type, char *s)
 {
 	extern int tabstops[];
 	extern int ntabstops;
@@ -672,9 +641,7 @@ opt_x(type, s)
  * Handler for the -" option.
  */
 	public void
-opt_quote(type, s)
-	int type;
-	register char *s;
+opt_quote(int type, char *s)
 {
 	char buf[3];
 	PARG parg;
@@ -715,9 +682,7 @@ opt_quote(type, s)
  */
 	/*ARGSUSED*/
 	public void
-opt_query(type, s)
-	int type;
-	char *s;
+opt_query(int type, char *s)
 {
 	switch (type)
 	{
@@ -734,7 +699,7 @@ opt_query(type, s)
  * Get the "screen window" size.
  */
 	public int
-get_swindow()
+get_swindow(void)
 {
 	if (swindow > 0)
 		return (swindow);
diff --git a/option.c b/option.c
index 256f5697b6b5..c5927e2c7722 100644
--- a/option.c
+++ b/option.c
@@ -23,8 +23,8 @@
 static struct loption *pendopt;
 public int plusoption = FALSE;
 
-static char *optstring();
-static int flip_triple();
+static char *optstring(char *s, char **p_str, char *printopt, char *validchars);
+static int flip_triple(int val, int lc);
 
 extern int screen_trashed;
 extern int less_is_more;
@@ -36,8 +36,7 @@ extern int opt_use_backslash;
  * Return a printable description of an option.
  */
 	static char *
-opt_desc(o)
-	struct loption *o;
+opt_desc(struct loption *o)
 {
 	static char buf[OPTNAME_MAX + 10];
 	if (o->oletter == OLETTER_NONE)
@@ -52,8 +51,7 @@ opt_desc(o)
  * For example, if the option letter is 'x', just return "-x".
  */
 	public char *
-propt(c)
-	int c;
+propt(int c)
 {
 	static char buf[8];
 
@@ -66,11 +64,10 @@ propt(c)
  * LESS environment variable) and process it.
  */
 	public void
-scan_option(s)
-	char *s;
+scan_option(char *s)
 {
-	register struct loption *o;
-	register int optc;
+	struct loption *o;
+	int optc;
 	char *optname;
 	char *printopt;
 	char *str;
@@ -299,13 +296,9 @@ scan_option(s)
  *	OPT_SET		set to the inverse of the default value
  */
 	public void
-toggle_option(o, lower, s, how_toggle)
-	struct loption *o;
-	int lower;
-	char *s;
-	int how_toggle;
+toggle_option(struct loption *o, int lower, char *s, int how_toggle)
 {
-	register int num;
+	int num;
 	int no_prompt;
 	int err;
 	PARG parg;
@@ -485,9 +478,7 @@ toggle_option(o, lower, s, how_toggle)
  * "Toggle" a triple-valued option.
  */
 	static int
-flip_triple(val, lc)
-	int val;
-	int lc;
+flip_triple(int val, int lc)
 {
 	if (lc)
 		return ((val == OPT_ON) ? OPT_OFF : OPT_ON);
@@ -499,8 +490,7 @@ flip_triple(val, lc)
  * Determine if an option takes a parameter.
  */
 	public int
-opt_has_param(o)
-	struct loption *o;
+opt_has_param(struct loption *o)
 {
 	if (o == NULL)
 		return (0);
@@ -514,8 +504,7 @@ opt_has_param(o)
  * Only string and number valued options have prompts.
  */
 	public char *
-opt_prompt(o)
-	struct loption *o;
+opt_prompt(struct loption *o)
 {
 	if (o == NULL || (o->otype & (STRING|NUMBER)) == 0)
 		return ("?");
@@ -530,7 +519,7 @@ opt_prompt(o)
  * the previous option.
  */
 	public int
-isoptpending()
+isoptpending(void)
 {
 	return (pendopt != NULL);
 }
@@ -539,8 +528,7 @@ isoptpending()
  * Print error message about missing string.
  */
 	static void
-nostring(printopt)
-	char *printopt;
+nostring(char *printopt)
 {
 	PARG parg;
 	parg.p_string = printopt;
@@ -551,7 +539,7 @@ nostring(printopt)
  * Print error message if a STRING type option is not followed by a string.
  */
 	public void
-nopendopt()
+nopendopt(void)
 {
 	nostring(opt_desc(pendopt));
 }
@@ -562,14 +550,10 @@ nopendopt()
  * Return a pointer to the remainder of the string, if any.
  */
 	static char *
-optstring(s, p_str, printopt, validchars)
-	char *s;
-	char **p_str;
-	char *printopt;
-	char *validchars;
+optstring(char *s, char **p_str, char *printopt, char *validchars)
 {
-	register char *p;
-	register char *out;
+	char *p;
+	char *out;
 
 	if (*s == '\0')
 	{
@@ -602,9 +586,7 @@ optstring(s, p_str, printopt, validchars)
 /*
  */
 	static int
-num_error(printopt, errp)
-	char *printopt;
-	int *errp;
+num_error(char *printopt, int *errp)
 {
 	PARG parg;
 
@@ -627,14 +609,11 @@ num_error(printopt, errp)
  * the char * to point after the translated number.
  */
 	public int
-getnum(sp, printopt, errp)
-	char **sp;
-	char *printopt;
-	int *errp;
+getnum(char **sp, char *printopt, int *errp)
 {
-	register char *s;
-	register int n;
-	register int neg;
+	char *s;
+	int n;
+	int neg;
 
 	s = skipsp(*sp);
 	neg = FALSE;
@@ -664,12 +643,9 @@ getnum(sp, printopt, errp)
  * That is, if "n" is returned, the fraction intended is n/NUM_FRAC_DENOM.
  */
 	public long
-getfraction(sp, printopt, errp)
-	char **sp;
-	char *printopt;
-	int *errp;
+getfraction(char **sp, char *printopt, int *errp)
 {
-	register char *s;
+	char *s;
 	long frac = 0;
 	int fraclen = 0;
 
@@ -699,7 +675,7 @@ getfraction(sp, printopt, errp)
  * Get the value of the -e flag.
  */
 	public int
-get_quit_at_eof()
+get_quit_at_eof(void)
 {
 	if (!less_is_more)
 		return quit_at_eof;
diff --git a/opttbl.c b/opttbl.c
index b896391aa3f2..096524f94d2b 100644
--- a/opttbl.c
+++ b/opttbl.c
@@ -464,9 +464,9 @@ static struct loption option[] =
  * Initialize each option to its default value.
  */
 	public void
-init_option()
+init_option(void)
 {
-	register struct loption *o;
+	struct loption *o;
 	char *p;
 
 	p = lgetenv("LESS_IS_MORE");
@@ -489,10 +489,9 @@ init_option()
  * Find an option in the option table, given its option letter.
  */
 	public struct loption *
-findopt(c)
-	int c;
+findopt(int c)
 {
-	register struct loption *o;
+	struct loption *o;
 
 	for (o = option;  o->oletter != '\0';  o++)
 	{
@@ -508,8 +507,7 @@ findopt(c)
  *
  */
 	static int
-is_optchar(c)
-	char c;
+is_optchar(char c)
 {
 	if (ASCII_IS_UPPER(c))
 		return 1;
@@ -527,15 +525,12 @@ is_optchar(c)
  * p_oname if non-NULL is set to point to the full option name.
  */
 	public struct loption *
-findopt_name(p_optname, p_oname, p_err)
-	char **p_optname;
-	char **p_oname;
-	int *p_err;
+findopt_name(char **p_optname, char **p_oname, int *p_err)
 {
 	char *optname = *p_optname;
-	register struct loption *o;
-	register struct optname *oname;
-	register int len;
+	struct loption *o;
+	struct optname *oname;
+	int len;
 	int uppercase;
 	struct loption *maxo = NULL;
 	struct optname *maxoname = NULL;
diff --git a/os.c b/os.c
index 530abe19d4cc..2daf7349fff7 100644
--- a/os.c
+++ b/os.c
@@ -60,12 +60,9 @@ extern int sigs;
  * any pending iread().
  */
 	public int
-iread(fd, buf, len)
-	int fd;
-	char *buf;
-	unsigned int len;
+iread(int fd, char *buf, unsigned int len)
 {
-	register int n;
+	int n;
 
 start:
 #if MSDOS_COMPILER==WIN32C
@@ -176,7 +173,7 @@ start:
  * Interrupt a pending iread().
  */
 	public void
-intread()
+intread(void)
 {
 	LONG_JUMP(read_label, 1);
 }
@@ -186,7 +183,7 @@ intread()
  */
 #if HAVE_TIME
 	public time_type
-get_time()
+get_time(void)
 {
 	time_type t;
 
@@ -201,8 +198,7 @@ get_time()
  * Local version of strerror, if not available from the system.
  */
 	static char *
-strerror(err)
-	int err;
+strerror(int err)
 {
 #if HAVE_SYS_ERRLIST
 	static char buf[16];
@@ -223,11 +219,10 @@ strerror(err)
  * errno_message: Return an error message based on the value of "errno".
  */
 	public char *
-errno_message(filename)
-	char *filename;
+errno_message(char *filename)
 {
-	register char *p;
-	register char *m;
+	char *p;
+	char *m;
 	int len;
 #if HAVE_ERRNO
 #if MUST_DEFINE_ERRNO
@@ -246,8 +241,7 @@ errno_message(filename)
 /* #define HAVE_FLOAT 0 */
 
 	static POSITION
-muldiv(val, num, den)
-	POSITION val, num, den;
+muldiv(POSITION val, POSITION num, POSITION den)
 {
 #if HAVE_FLOAT
 	double v = (((double) val) * num) / den;
@@ -270,8 +264,7 @@ muldiv(val, num, den)
  * {{ Assumes a POSITION is a long int. }}
  */
 	public int
-percentage(num, den)
-	POSITION num, den;
+percentage(POSITION num, POSITION den)
 {
 	return (int) muldiv(num,  (POSITION) 100, den);
 }
@@ -280,10 +273,7 @@ percentage(num, den)
  * Return the specified percentage of a POSITION.
  */
 	public POSITION
-percent_pos(pos, percent, fraction)
-	POSITION pos;
-	int percent;
-	long fraction;
+percent_pos(POSITION pos, int percent, long fraction)
 {
 	/* Change percent (parts per 100) to perden (parts per NUM_FRAC_DENOM). */
 	POSITION perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100);
@@ -334,9 +324,7 @@ memcpy(dst, src, len)
  * This implements an ANSI-style intercept setup for Microware C 3.2
  */
 	public int 
-os9_signal(type, handler)
-	int type;
-	RETSIGTYPE (*handler)();
+os9_signal(int type, RETSIGTYPE (*handler)())
 {
 	intercept(handler);
 }
diff --git a/output.c b/output.c
index d6cfc3826720..4d1e2aaae540 100644
--- a/output.c
+++ b/output.c
@@ -43,10 +43,10 @@ extern int bl_fg_color, bl_bg_color;
  * Display the line which is in the line buffer.
  */
 	public void
-put_line()
+put_line(void)
 {
-	register int c;
-	register int i;
+	int c;
+	int i;
 	int a;
 
 	if (ABORT_SIGS())
@@ -93,10 +93,10 @@ static char *ob = obuf;
  * overwritten or scrolled away.
  */
 	public void
-flush()
+flush(void)
 {
-	register int n;
-	register int fd;
+	int n;
+	int fd;
 
 	n = (int) (ob - obuf);
 	if (n == 0)
@@ -326,8 +326,7 @@ flush()
  * Output a character.
  */
 	public int
-putchr(c)
-	int c;
+putchr(int c)
 {
 #if 0 /* fake UTF-8 output for testing */
 	extern int utf_mode;
@@ -380,8 +379,7 @@ putchr(c)
  * Output a string.
  */
 	public void
-putstr(s)
-	register char *s;
+putstr(constant char *s)
 {
 	while (*s != '\0')
 		putchr(*s++);
@@ -398,7 +396,7 @@ void funcname(num, buf) \
 { \
 	int neg = (num < 0); \
 	char tbuf[INT_STRLEN_BOUND(num)+2]; \
-	register char *s = tbuf + sizeof(tbuf); \
+	char *s = tbuf + sizeof(tbuf); \
 	if (neg) num = -num; \
 	*--s = '\0'; \
 	do { \
@@ -416,8 +414,7 @@ TYPE_TO_A_FUNC(inttoa, int)
  * Output an integer in a given radix.
  */
 	static int
-iprint_int(num)
-	int num;
+iprint_int(int num)
 {
 	char buf[INT_STRLEN_BOUND(num)];
 
@@ -430,8 +427,7 @@ iprint_int(num)
  * Output a line number in a given radix.
  */
 	static int
-iprint_linenum(num)
-	LINENUM num;
+iprint_linenum(LINENUM num)
 {
 	char buf[INT_STRLEN_BOUND(num)];
 
@@ -445,12 +441,10 @@ iprint_linenum(num)
  * using a more portable argument list mechanism than printf's.
  */
 	static int
-less_printf(fmt, parg)
-	register char *fmt;
-	PARG *parg;
+less_printf(char *fmt, PARG *parg)
 {
-	register char *s;
-	register int col;
+	char *s;
+	int col;
 
 	col = 0;
 	while (*fmt != '\0')
@@ -493,7 +487,7 @@ less_printf(fmt, parg)
  * become the next command.
  */
 	public void
-get_return()
+get_return(void)
 {
 	int c;
 
@@ -512,9 +506,7 @@ get_return()
  * and wait for carriage return.
  */
 	public void
-error(fmt, parg)
-	char *fmt;
-	PARG *parg;
+error(char *fmt, PARG *parg)
 {
 	int col = 0;
 	static char return_to_continue[] = "  (press RETURN)";
@@ -567,9 +559,7 @@ static char intr_to_abort[] = "... (interrupt to abort)";
  * time-consuming operation.
  */
 	public void
-ierror(fmt, parg)
-	char *fmt;
-	PARG *parg;
+ierror(char *fmt, PARG *parg)
 {
 	at_exit();
 	clear_bot();
@@ -586,11 +576,9 @@ ierror(fmt, parg)
  * and return a single-character response.
  */
 	public int
-query(fmt, parg)
-	char *fmt;
-	PARG *parg;
+query(char *fmt, PARG *parg)
 {
-	register int c;
+	int c;
 	int col = 0;
 
 	if (any_display && is_tty)
diff --git a/pattern.c b/pattern.c
index 71141c7d05fe..0706f7258819 100644
--- a/pattern.c
+++ b/pattern.c
@@ -20,11 +20,7 @@ extern int caseless;
  * Compile a search pattern, for future use by match_pattern.
  */
 	static int
-compile_pattern2(pattern, search_type, comp_pattern, show_error)
-	char *pattern;
-	int search_type;
-	void **comp_pattern;
-	int show_error;
+compile_pattern2(char *pattern, int search_type, void **comp_pattern, int show_error)
 {
 	if (search_type & SRCH_NO_REGEX)
 		return (0);
@@ -127,10 +123,7 @@ compile_pattern2(pattern, search_type, comp_pattern, show_error)
  * Like compile_pattern2, but convert the pattern to lowercase if necessary.
  */
 	public int
-compile_pattern(pattern, search_type, comp_pattern)
-	char *pattern;
-	int search_type;
-	void **comp_pattern;
+compile_pattern(char *pattern, int search_type, void **comp_pattern)
 {
 	char *cvt_pattern;
 	int result;
@@ -152,8 +145,7 @@ compile_pattern(pattern, search_type, comp_pattern)
  * Forget that we have a compiled pattern.
  */
 	public void
-uncompile_pattern(pattern)
-	void **pattern;
+uncompile_pattern(void **pattern)
 {
 #if HAVE_GNU_REGEX
 	struct re_pattern_buffer **pcomp = (struct re_pattern_buffer **) pattern;
@@ -195,8 +187,7 @@ uncompile_pattern(pattern)
  * Can a pattern be successfully compiled?
  */
 	public int
-valid_pattern(pattern)
-	char *pattern;
+valid_pattern(char *pattern)
 {
 	void *comp_pattern;
 	int result;
@@ -213,8 +204,7 @@ valid_pattern(pattern)
  * Is a compiled pattern null?
  */
 	public int
-is_null_pattern(pattern)
-	void *pattern;
+is_null_pattern(void *pattern)
 {
 #if HAVE_GNU_REGEX
 	return (pattern == NULL);
@@ -244,16 +234,11 @@ is_null_pattern(pattern)
  * It supports no metacharacters like *, etc.
  */
 	static int
-match(pattern, pattern_len, buf, buf_len, pfound, pend)
-	char *pattern;
-	int pattern_len;
-	char *buf;
-	int buf_len;
-	char **pfound, **pend;
+match(char *pattern, int pattern_len, char *buf, int buf_len, char **pfound, char **pend)
 {
-	register char *pp, *lp;
-	register char *pattern_end = pattern + pattern_len;
-	register char *buf_end = buf + buf_len;
+	char *pp, *lp;
+	char *pattern_end = pattern + pattern_len;
+	char *buf_end = buf + buf_len;
 
 	for ( ;  buf < buf_end;  buf++)
 	{
@@ -285,15 +270,7 @@ match(pattern, pattern_len, buf, buf_len, pfound, pend)
  * Set sp and ep to the start and end of the matched string.
  */
 	public int
-match_pattern(pattern, tpattern, line, line_len, sp, ep, notbol, search_type)
-	void *pattern;
-	char *tpattern;
-	char *line;
-	int line_len;
-	char **sp;
-	char **ep;
-	int notbol;
-	int search_type;
+match_pattern(void *pattern, char *tpattern, char *line, int line_len, char **sp, char **ep, int notbol, int search_type)
 {
 	int matched;
 #if HAVE_GNU_REGEX
diff --git a/position.c b/position.c
index dc80fd636154..a0e4e3a64417 100644
--- a/position.c
+++ b/position.c
@@ -36,8 +36,7 @@ extern int sc_width, sc_height;
  *	the line after the bottom line on the screen
  */
 	public POSITION
-position(where)
-	int where;
+position(int where)
 {
 	switch (where)
 	{
@@ -57,10 +56,9 @@ position(where)
  * Add a new file position to the bottom of the position table.
  */
 	public void
-add_forw_pos(pos)
-	POSITION pos;
+add_forw_pos(POSITION pos)
 {
-	register int i;
+	int i;
 
 	/*
 	 * Scroll the position table up.
@@ -74,10 +72,9 @@ add_forw_pos(pos)
  * Add a new file position to the top of the position table.
  */
 	public void
-add_back_pos(pos)
-	POSITION pos;
+add_back_pos(POSITION pos)
 {
-	register int i;
+	int i;
 
 	/*
 	 * Scroll the position table down.
@@ -91,9 +88,9 @@ add_back_pos(pos)
  * Initialize the position table, done whenever we clear the screen.
  */
 	public void
-pos_clear()
+pos_clear(void)
 {
-	register int i;
+	int i;
 
 	for (i = 0;  i < sc_height;  i++)
 		table[i] = NULL_POSITION;
@@ -103,7 +100,7 @@ pos_clear()
  * Allocate or reallocate the position table.
  */
 	public void
-pos_init()
+pos_init(void)
 {
 	struct scrpos scrpos;
 
@@ -132,10 +129,9 @@ pos_init()
  * Return the position table entry if found, -1 if not.
  */
 	public int
-onscreen(pos)
-	POSITION pos;
+onscreen(POSITION pos)
 {
-	register int i;
+	int i;
 
 	if (pos < table[0])
 		return (-1);
@@ -149,17 +145,15 @@ onscreen(pos)
  * See if the entire screen is empty.
  */
 	public int
-empty_screen()
+empty_screen(void)
 {
 	return (empty_lines(0, sc_height-1));
 }
 
 	public int
-empty_lines(s, e)
-	int s;
-	int e;
+empty_lines(int s, int e)
 {
-	register int i;
+	int i;
 
 	for (i = s;  i <= e;  i++)
 		if (table[i] != NULL_POSITION && table[i] != 0)
@@ -176,10 +170,9 @@ empty_lines(s, e)
  * the screen line to a number > 0.
  */
 	public void
-get_scrpos(scrpos)
-	struct scrpos *scrpos;
+get_scrpos(struct scrpos *scrpos)
 {
-	register int i;
+	int i;
 
 	/*
 	 * Find the first line on the screen which has something on it,
@@ -208,8 +201,7 @@ get_scrpos(scrpos)
  * relative to the bottom of the screen.
  */
 	public int
-adjsline(sline)
-	int sline;
+adjsline(int sline)
 {
 	/*
 	 * Negative screen line number means
diff --git a/prompt.c b/prompt.c
index 50ced97bf713..c53f27351bfb 100644
--- a/prompt.c
+++ b/prompt.c
@@ -66,7 +66,7 @@ static char *mp;
  * Initialize the prompt prototype strings.
  */
 	public void
-init_prompt()
+init_prompt(void)
 {
 	prproto[0] = save(s_proto);
 	prproto[1] = save(less_is_more ? more_proto : m_proto);
@@ -80,8 +80,7 @@ init_prompt()
  * Append a string to the end of the message.
  */
 	static void
-ap_str(s)
-	char *s;
+ap_str(char *s)
 {
 	int len;
 
@@ -97,8 +96,7 @@ ap_str(s)
  * Append a character to the end of the message.
  */
 	static void
-ap_char(c)
-	char c;
+ap_char(char c)
 {
 	char buf[2];
 
@@ -111,8 +109,7 @@ ap_char(c)
  * Append a POSITION (as a decimal integer) to the end of the message.
  */
 	static void
-ap_pos(pos)
-	POSITION pos;
+ap_pos(POSITION pos)
 {
 	char buf[INT_STRLEN_BOUND(pos) + 2];
 
@@ -124,8 +121,7 @@ ap_pos(pos)
  * Append a line number to the end of the message.
  */
  	static void
-ap_linenum(linenum)
-	LINENUM linenum;
+ap_linenum(LINENUM linenum)
 {
 	char buf[INT_STRLEN_BOUND(linenum) + 2];
 
@@ -137,8 +133,7 @@ ap_linenum(linenum)
  * Append an integer to the end of the message.
  */
 	static void
-ap_int(num)
-	int num;
+ap_int(int num)
 {
 	char buf[INT_STRLEN_BOUND(num) + 2];
 
@@ -150,7 +145,7 @@ ap_int(num)
  * Append a question mark to the end of the message.
  */
 	static void
-ap_quest()
+ap_quest(void)
 {
 	ap_str("?");
 }
@@ -159,8 +154,7 @@ ap_quest()
  * Return the "current" byte offset in the file.
  */
 	static POSITION
-curr_byte(where)
-	int where;
+curr_byte(int where)
 {
 	POSITION pos;
 
@@ -179,9 +173,7 @@ curr_byte(where)
  * Here we decode that letter and return the appropriate boolean value.
  */
 	static int
-cond(c, where)
-	char c;
-	int where;
+cond(char c, int where)
 {
 	POSITION len;
 
@@ -243,10 +235,7 @@ cond(c, where)
  * usually by appending something to the message being built.
  */
 	static void
-protochar(c, where, iseditproto)
-	int c;
-	int where;
-	int iseditproto;
+protochar(int c, int where, int iseditproto)
 {
 	POSITION pos;
 	POSITION len;
@@ -393,10 +382,9 @@ protochar(c, where, iseditproto)
  * We must keep track of nested IFs and skip them properly.
  */
 	static constant char *
-skipcond(p)
-	register constant char *p;
+skipcond(constant char *p)
 {
-	register int iflevel;
+	int iflevel;
 
 	/*
 	 * We came in here after processing a ? or :,
@@ -451,9 +439,7 @@ skipcond(p)
  * Decode a char that represents a position on the screen.
  */
 	static constant char *
-wherechar(p, wp)
-	char constant *p;
-	int *wp;
+wherechar(char constant *p, int *wp)
 {
 	switch (*p)
 	{
@@ -475,12 +461,10 @@ wherechar(p, wp)
  * Construct a message based on a prototype string.
  */
 	public char *
-pr_expand(proto, maxwidth)
-	constant char *proto;
-	int maxwidth;
+pr_expand(constant char *proto, int maxwidth)
 {
-	register constant char *p;
-	register int c;
+	constant char *p;
+	int c;
 	int where;
 
 	mp = message;
@@ -551,7 +535,7 @@ pr_expand(proto, maxwidth)
  * Return a message suitable for printing by the "=" command.
  */
 	public char *
-eq_message()
+eq_message(void)
 {
 	return (pr_expand(eqproto, 0));
 }
@@ -563,7 +547,7 @@ eq_message()
  * and the caller will prompt with a colon.
  */
 	public char *
-pr_string()
+pr_string(void)
 {
 	char *prompt;
 	int type;
@@ -580,7 +564,7 @@ pr_string()
  * Return a message suitable for printing while waiting in the F command.
  */
 	public char *
-wait_message()
+wait_message(void)
 {
 	return (pr_expand(wproto, sc_width-so_s_width-so_e_width-2));
 }
diff --git a/regexp.c b/regexp.c
index fcf7c9a83605..b54c8f07ccc3 100644
--- a/regexp.c
+++ b/regexp.c
@@ -207,13 +207,12 @@ STATIC int strcspn();
  * of the structure of the compiled regexp.
  */
 regexp *
-regcomp(exp)
-char *exp;
+regcomp(char *exp)
 {
-	register regexp *r;
-	register char *scan;
-	register char *longest;
-	register int len;
+	regexp *r;
+	char *scan;
+	char *longest;
+	int len;
 	int flags;
 
 	if (exp == NULL)
@@ -297,14 +296,12 @@ char *exp;
  * follows makes it hard to avoid.
  */
 static char *
-reg(paren, flagp)
-int paren;			/* Parenthesized? */
-int *flagp;
+reg(int paren, int *flagp)
 {
-	register char *ret;
-	register char *br;
-	register char *ender;
-	register int parno = 0;
+	char *ret;
+	char *br;
+	char *ender;
+	int parno = 0;
 	int flags;
 
 	*flagp = HASWIDTH;	/* Tentatively. */
@@ -369,12 +366,11 @@ int *flagp;
  * Implements the concatenation operator.
  */
 static char *
-regbranch(flagp)
-int *flagp;
+regbranch(int *flagp)
 {
-	register char *ret;
-	register char *chain;
-	register char *latest;
+	char *ret;
+	char *chain;
+	char *latest;
 	int flags;
 
 	*flagp = WORST;		/* Tentatively. */
@@ -408,12 +404,11 @@ int *flagp;
  * endmarker role is not redundant.
  */
 static char *
-regpiece(flagp)
-int *flagp;
+regpiece(int *flagp)
 {
-	register char *ret;
-	register char op;
-	register char *next;
+	char *ret;
+	char op;
+	char *next;
 	int flags;
 
 	ret = regatom(&flags);
@@ -472,10 +467,9 @@ int *flagp;
  * separate node; the code is simpler that way and it's not worth fixing.
  */
 static char *
-regatom(flagp)
-int *flagp;
+regatom(int *flagp)
 {
-	register char *ret;
+	char *ret;
 	int flags;
 
 	*flagp = WORST;		/* Tentatively. */
@@ -492,8 +486,8 @@ int *flagp;
 		*flagp |= HASWIDTH|SIMPLE;
 		break;
 	case '[': {
-			register int clss;
-			register int classend;
+			int clss;
+			int classend;
 
 			if (*regparse == '^') {	/* Complement of range. */
 				ret = regnode(ANYBUT);
@@ -553,8 +547,8 @@ int *flagp;
 		*flagp |= HASWIDTH|SIMPLE;
 		break;
 	default: {
-			register int len;
-			register char ender;
+			int len;
+			char ender;
 
 			regparse--;
 			len = (int) strcspn(regparse, META);
@@ -583,11 +577,10 @@ int *flagp;
  - regnode - emit a node
  */
 static char *			/* Location. */
-regnode(op)
-char op;
+regnode(char op)
 {
-	register char *ret;
-	register char *ptr;
+	char *ret;
+	char *ptr;
 
 	ret = regcode;
 	if (ret == &regdummy) {
@@ -608,8 +601,7 @@ char op;
  - regc - emit (if appropriate) a byte of code
  */
 static void
-regc(b)
-char b;
+regc(char b)
 {
 	if (regcode != &regdummy)
 		*regcode++ = b;
@@ -623,13 +615,11 @@ char b;
  * Means relocating the operand.
  */
 static void
-reginsert(op, opnd)
-char op;
-char *opnd;
+reginsert(char op, char *opnd)
 {
-	register char *src;
-	register char *dst;
-	register char *place;
+	char *src;
+	char *dst;
+	char *place;
 
 	if (regcode == &regdummy) {
 		regsize += 3;
@@ -652,13 +642,11 @@ char *opnd;
  - regtail - set the next-pointer at the end of a node chain
  */
 static void
-regtail(p, val)
-char *p;
-char *val;
+regtail(char *p, char *val)
 {
-	register char *scan;
-	register char *temp;
-	register int offset;
+	char *scan;
+	char *temp;
+	int offset;
 
 	if (p == &regdummy)
 		return;
@@ -684,9 +672,7 @@ char *val;
  - regoptail - regtail on operand of first argument; nop if operandless
  */
 static void
-regoptail(p, val)
-char *p;
-char *val;
+regoptail(char *p, char *val)
 {
 	/* "Operandless" and "op != BRANCH" are synonymous in practice. */
 	if (p == NULL || p == &regdummy || OP(p) != BRANCH)
@@ -723,12 +709,9 @@ STATIC char *regprop();
  - regexec - match a regexp against a string
  */
 int
-regexec2(prog, string, notbol)
-register regexp *prog;
-register char *string;
-int notbol;
+regexec2(regexp *prog, char *string, int notbol)
 {
-	register char *s;
+	char *s;
 
 	/* Be paranoid... */
 	if (prog == NULL || string == NULL) {
@@ -785,9 +768,7 @@ int notbol;
 }
 
 int
-regexec(prog, string)
-register regexp *prog;
-register char *string;
+regexec(regexp *prog, char *string)
 {
 	return regexec2(prog, string, 0);
 }
@@ -796,13 +777,11 @@ register char *string;
  - regtry - try match at specific point
  */
 static int			/* 0 failure, 1 success */
-regtry(prog, string)
-regexp *prog;
-char *string;
+regtry(regexp *prog, char *string)
 {
-	register int i;
-	register char **sp;
-	register char **ep;
+	int i;
+	char **sp;
+	char **ep;
 
 	reginput = string;
 	regstartp = prog->startp;
@@ -833,11 +812,10 @@ char *string;
  * by recursion.
  */
 static int			/* 0 failure, 1 success */
-regmatch(prog)
-char *prog;
+regmatch(char *prog)
 {
-	register char *scan;	/* Current node. */
-	char *next;		/* Next node. */
+	char *scan;	/* Current node. */
+	char *next;	/* Next node. */
 
 	scan = prog;
 #ifdef DEBUG
@@ -866,8 +844,8 @@ char *prog;
 			reginput++;
 			break;
 		case EXACTLY: {
-				register int len;
-				register char *opnd;
+				int len;
+				char *opnd;
 
 				opnd = OPERAND(scan);
 				/* Inline the first character, for speed. */
@@ -902,8 +880,8 @@ char *prog;
 		case OPEN+7:
 		case OPEN+8:
 		case OPEN+9: {
-				register int no;
-				register char *save;
+				int no;
+				char *save;
 
 				no = OP(scan) - OPEN;
 				save = reginput;
@@ -931,8 +909,8 @@ char *prog;
 		case CLOSE+7:
 		case CLOSE+8:
 		case CLOSE+9: {
-				register int no;
-				register char *save;
+				int no;
+				char *save;
 
 				no = OP(scan) - CLOSE;
 				save = reginput;
@@ -952,7 +930,7 @@ char *prog;
 			/* NOTREACHED */
 			break;
 		case BRANCH: {
-				register char *save;
+				char *save;
 
 				if (OP(next) != BRANCH)		/* No choice. */
 					next = OPERAND(scan);	/* Avoid recursion. */
@@ -972,10 +950,10 @@ char *prog;
 			break;
 		case STAR:
 		case PLUS: {
-				register char nextch;
-				register int no;
-				register char *save;
-				register int min;
+				char nextch;
+				int no;
+				char *save;
+				int min;
 
 				/*
 				 * Lookahead to avoid useless match attempts
@@ -1026,12 +1004,11 @@ char *prog;
  - regrepeat - repeatedly match something simple, report how many
  */
 static int
-regrepeat(p)
-char *p;
+regrepeat(char *p)
 {
-	register int count = 0;
-	register char *scan;
-	register char *opnd;
+	int count = 0;
+	char *scan;
+	char *opnd;
 
 	scan = reginput;
 	opnd = OPERAND(p);
@@ -1072,10 +1049,9 @@ char *p;
  - regnext - dig the "next" pointer out of a node
  */
 static char *
-regnext(p)
-register char *p;
+regnext(char *p)
 {
-	register int offset;
+	int offset;
 
 	if (p == &regdummy)
 		return(NULL);
@@ -1098,12 +1074,11 @@ STATIC char *regprop();
  - regdump - dump a regexp onto stdout in vaguely comprehensible form
  */
 void
-regdump(r)
-regexp *r;
+regdump(regexp *r)
 {
-	register char *s;
-	register char op = EXACTLY;	/* Arbitrary non-END op. */
-	register char *next;
+	char *s;
+	char op = EXACTLY;	/* Arbitrary non-END op. */
+	char *next;
 
 
 	s = r->program + 1;
@@ -1141,10 +1116,9 @@ regexp *r;
  - regprop - printable representation of opcode
  */
 static char *
-regprop(op)
-char *op;
+regprop(char *op)
 {
-	register char *p;
+	char *p;
 	static char buf[50];
 
 	(void) strcpy(buf, ":");
@@ -1233,13 +1207,11 @@ char *op;
  */
 
 static int
-strcspn(s1, s2)
-char *s1;
-char *s2;
+strcspn(char *s1, char *s2)
 {
-	register char *scan1;
-	register char *scan2;
-	register int count;
+	char *scan1;
+	char *scan2;
+	int count;
 
 	count = 0;
 	for (scan1 = s1; *scan1 != '\0'; scan1++) {
diff --git a/screen.c b/screen.c
index 8f8a433aff64..8ae52fac80d8 100644
--- a/screen.c
+++ b/screen.c
@@ -205,8 +205,9 @@ static int attrmode = AT_NORMAL;
 extern int binattr;
 
 #if !MSDOS_COMPILER
-static char *cheaper();
-static void tmodes();
+static char *cheaper(char *t1, char *t2, char *def);
+static void tmodes(char *incap, char *outcap, char **instr, char **outstr,
+	char *def_instr, char *def_outstr, char **spp);
 #endif
 
 /*
@@ -253,8 +254,7 @@ extern char *tgoto();
  * It doesn't matter whether an input \n is mapped to \r, or vice versa.
  */
 	public void
-raw_mode(on)
-	int on;
+raw_mode(int on)
 {
 	static int curr_on = 0;
 
@@ -618,8 +618,7 @@ raw_mode(on)
 static int hardcopy;
 
 	static char *
-ltget_env(capname)
-	char *capname;
+ltget_env(char *capname)
 {
 	char name[16];
 	char *s;
@@ -647,8 +646,7 @@ ltget_env(capname)
 }
 
 	static int
-ltgetflag(capname)
-	char *capname;
+ltgetflag(char *capname)
 {
 	char *s;
 
@@ -660,8 +658,7 @@ ltgetflag(capname)
 }
 
 	static int
-ltgetnum(capname)
-	char *capname;
+ltgetnum(char *capname)
 {
 	char *s;
 
@@ -673,9 +670,7 @@ ltgetnum(capname)
 }
 
 	static char *
-ltgetstr(capname, pp)
-	char *capname;
-	char **pp;
+ltgetstr(char *capname, char **pp)
 {
 	char *s;
 
@@ -691,9 +686,9 @@ ltgetstr(capname, pp)
  * Get size of the output screen.
  */
 	public void
-scrsize()
+scrsize(void)
 {
-	register char *s;
+	char *s;
 	int sys_height;
 	int sys_width;
 #if !MSDOS_COMPILER
@@ -821,7 +816,7 @@ scrsize()
  * Figure out how many empty loops it takes to delay a millisecond.
  */
 	static void
-get_clock()
+get_clock(void)
 {
 	clock_t start;
 	
@@ -849,15 +844,14 @@ get_clock()
  * Delay for a specified number of milliseconds.
  */
 	static void
-dummy_func()
+dummy_func(void)
 {
 	static long delay_dummy = 0;
 	delay_dummy++;
 }
 
 	static void
-delay(msec)
-	int msec;
+delay(int msec)
 {
 	long i;
 	
@@ -879,8 +873,7 @@ delay(msec)
  * Return the characters actually input by a "special" key.
  */
 	public char *
-special_key_str(key)
-	int key;
+special_key_str(int key)
 {
 	static char tbuf[40];
 	char *s;
@@ -1052,7 +1045,7 @@ special_key_str(key)
  * Get terminal capabilities via termcap.
  */
 	public void
-get_term()
+get_term(void)
 {
 #if MSDOS_COMPILER
 	auto_wrap = 1;
@@ -1117,7 +1110,7 @@ get_term()
 #else /* !MSDOS_COMPILER */
 
 	char *sp;
-	register char *t1, *t2;
+	char *t1, *t2;
 	char *term;
 	char termbuf[TERMBUF_SIZE];
 
@@ -1349,16 +1342,14 @@ static int costcount;
 
 /*ARGSUSED*/
 	static int
-inc_costcount(c)
-	int c;
+inc_costcount(int c)
 {
 	costcount++;
 	return (c);
 }
 
 	static int
-cost(t)
-	char *t;
+cost(char *t)
 {
 	costcount = 0;
 	tputs(t, sc_height, inc_costcount);
@@ -1371,9 +1362,7 @@ cost(t)
  * cost (see cost() function).
  */
 	static char *
-cheaper(t1, t2, def)
-	char *t1, *t2;
-	char *def;
+cheaper(char *t1, char *t2, char *def)
 {
 	if (*t1 == '\0' && *t2 == '\0')
 	{
@@ -1390,14 +1379,8 @@ cheaper(t1, t2, def)
 }
 
 	static void
-tmodes(incap, outcap, instr, outstr, def_instr, def_outstr, spp)
-	char *incap;
-	char *outcap;
-	char **instr;
-	char **outstr;
-	char *def_instr;
-	char *def_outstr;
-	char **spp;
+tmodes(char *incap, char *outcap, char **instr, char **outstr, char *def_instr,
+    char *def_outstr, char **spp)
 {
 	*instr = ltgetstr(incap, spp);
 	if (*instr == NULL)
@@ -1446,7 +1429,7 @@ _settextposition(int row, int col)
  * Initialize the screen to the correct color at startup.
  */
 	static void
-initcolor()
+initcolor(void)
 {
 	SETCOLORS(nm_fg_color, nm_bg_color);
 #if 0
@@ -1479,7 +1462,7 @@ initcolor()
  * Termcap-like init with a private win32 console.
  */
 	static void
-win32_init_term()
+win32_init_term(void)
 {
 	CONSOLE_SCREEN_BUFFER_INFO scr;
 	COORD size;
@@ -1530,7 +1513,7 @@ win32_deinit_term()
  * Initialize terminal
  */
 	public void
-init()
+init(void)
 {
 #if !MSDOS_COMPILER
 	if (!no_init)
@@ -1566,7 +1549,7 @@ init()
  * Deinitialize terminal
  */
 	public void
-deinit()
+deinit(void)
 {
 	if (!init_done)
 		return;
@@ -1593,7 +1576,7 @@ deinit()
  * Home cursor (move to upper left corner of screen).
  */
 	public void
-home()
+home(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_home, 1, putchr);
@@ -1608,7 +1591,7 @@ home()
  * Should scroll the display down.
  */
 	public void
-add_line()
+add_line(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_addline, sc_height, putchr);
@@ -1666,8 +1649,7 @@ add_line()
  * into the scrollback buffer when we go down-one-line (in WIN32).
  */
 	public void
-remove_top(n)
-	int n;
+remove_top(int n)
 {
 #if MSDOS_COMPILER==WIN32C
 	SMALL_RECT rcSrc, rcClip;
@@ -1720,7 +1702,7 @@ remove_top(n)
  * Clear the screen.
  */
 	static void
-win32_clear()
+win32_clear(void)
 {
 	/*
 	 * This will clear only the currently visible rows of the NT
@@ -1751,8 +1733,7 @@ win32_clear()
  * window upward.
  */
 	public void
-win32_scroll_up(n)
-	int n;
+win32_scroll_up(int n)
 {
 	SMALL_RECT rcSrc, rcClip;
 	CHAR_INFO fillchar;
@@ -1817,7 +1798,7 @@ win32_scroll_up(n)
  * Move cursor to lower left corner of screen.
  */
 	public void
-lower_left()
+lower_left(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_lower_left, 1, putchr);
@@ -1831,7 +1812,7 @@ lower_left()
  * Move cursor to left position of current line.
  */
 	public void
-line_left()
+line_left(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_return, 1, putchr);
@@ -1863,7 +1844,7 @@ line_left()
  * (in lieu of SIGWINCH for WIN32).
  */
 	public void
-check_winch()
+check_winch(void)
 {
 #if MSDOS_COMPILER==WIN32C
 	CONSOLE_SCREEN_BUFFER_INFO scr;
@@ -1893,8 +1874,7 @@ check_winch()
  * Goto a specific line on the screen.
  */
 	public void
-goto_line(slinenum)
-	int slinenum;
+goto_line(int slinenum)
 {
 #if !MSDOS_COMPILER
 	tputs(tgoto(sc_move, 0, slinenum), 1, putchr);
@@ -1912,7 +1892,7 @@ goto_line(slinenum)
  * {{ Yuck!  There must be a better way to get a visual bell. }}
  */
 	static void
-create_flash()
+create_flash(void)
 {
 #if MSDOS_COMPILER==MSOFTC
 	struct videoconfig w;
@@ -1941,7 +1921,7 @@ create_flash()
 	}
 #else
 #if MSDOS_COMPILER==BORLANDC
-	register int n;
+	int n;
 
 	whitescreen = (unsigned short *) 
 		malloc(sc_width * sc_height * sizeof(short));
@@ -1951,7 +1931,7 @@ create_flash()
 		whitescreen[n] = 0x7020;
 #else
 #if MSDOS_COMPILER==WIN32C
-	register int n;
+	int n;
 
 	whitescreen = (WORD *)
 		malloc(sc_height * sc_width * sizeof(WORD));
@@ -1971,7 +1951,7 @@ create_flash()
  * Output the "visual bell", if there is one.
  */
 	public void
-vbell()
+vbell(void)
 {
 #if !MSDOS_COMPILER
 	if (*sc_visual_bell == '\0')
@@ -2035,7 +2015,7 @@ vbell()
  * Make a noise.
  */
 	static void
-beep()
+beep(void)
 {
 #if !MSDOS_COMPILER
 	putchr(CONTROL('G'));
@@ -2052,7 +2032,7 @@ beep()
  * Ring the terminal bell.
  */
 	public void
-bell()
+bell(void)
 {
 	if (quiet == VERY_QUIET)
 		vbell();
@@ -2064,7 +2044,7 @@ bell()
  * Clear the screen.
  */
 	public void
-clear()
+clear(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_clear, sc_height, putchr);
@@ -2083,7 +2063,7 @@ clear()
  * {{ This must not move the cursor. }}
  */
 	public void
-clear_eol()
+clear_eol(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_eol_clear, 1, putchr);
@@ -2142,7 +2122,7 @@ clear_eol()
  * Clear the screen if there's off-screen memory below the display.
  */
 	static void
-clear_eol_bot()
+clear_eol_bot(void)
 {
 #if MSDOS_COMPILER
 	clear_eol();
@@ -2159,7 +2139,7 @@ clear_eol_bot()
  * Leave the cursor at the beginning of the bottom line.
  */
 	public void
-clear_bot()
+clear_bot(void)
 {
 	/*
 	 * If we're in a non-normal attribute mode, temporarily exit
@@ -2184,8 +2164,7 @@ clear_bot()
 }
 
 	public void
-at_enter(attr)
-	int attr;
+at_enter(int attr)
 {
 	attr = apply_at_specials(attr);
 
@@ -2223,7 +2202,7 @@ at_enter(attr)
 }
 
 	public void
-at_exit()
+at_exit(void)
 {
 #if !MSDOS_COMPILER
 	/* Undo things in the reverse order we did them.  */
@@ -2244,8 +2223,7 @@ at_exit()
 }
 
 	public void
-at_switch(attr)
-	int attr;
+at_switch(int attr)
 {
 	int new_attrmode = apply_at_specials(attr);
 	int ignore_modes = AT_ANSI;
@@ -2258,9 +2236,7 @@ at_switch(attr)
 }
 
 	public int
-is_at_equiv(attr1, attr2)
-	int attr1;
-	int attr2;
+is_at_equiv(int attr1, int attr2)
 {
 	attr1 = apply_at_specials(attr1);
 	attr2 = apply_at_specials(attr2);
@@ -2269,8 +2245,7 @@ is_at_equiv(attr1, attr2)
 }
 
 	public int
-apply_at_specials(attr)
-	int attr;
+apply_at_specials(int attr)
 {
 	if (attr & AT_BINARY)
 		attr |= binattr;
@@ -2287,7 +2262,7 @@ apply_at_specials(attr)
  * and move the cursor left.
  */
 	public void
-backspace()
+backspace(void)
 {
 #if !MSDOS_COMPILER
 	/* 
@@ -2336,7 +2311,7 @@ backspace()
  * Output a plain backspace, without erasing the previous char.
  */
 	public void
-putbs()
+putbs(void)
 {
 #if !MSDOS_COMPILER
 	tputs(sc_backspace, 1, putchr);
@@ -2375,8 +2350,7 @@ putbs()
  * Determine whether an input character is waiting to be read.
  */
 	static int
-win32_kbhit(tty)
-	HANDLE tty;
+win32_kbhit(HANDLE tty)
 {
 	INPUT_RECORD ip;
 	DWORD read;
@@ -2440,8 +2414,7 @@ win32_kbhit(tty)
  * Read a character from the keyboard.
  */
 	public char
-WIN32getch(tty)
-	int tty;
+WIN32getch(int tty)
 {
 	int ascii;
 
@@ -2474,9 +2447,7 @@ WIN32getch(tty)
 /*
  */
 	public void
-WIN32setcolors(fg, bg)
-	int fg;
-	int bg;
+WIN32setcolors(int fg, int bg)
 {
 	SETCOLORS(fg, bg);
 }
@@ -2484,9 +2455,7 @@ WIN32setcolors(fg, bg)
 /*
  */
 	public void
-WIN32textout(text, len)
-	char *text;
-	int len;
+WIN32textout(char *text, int len)
 {
 #if MSDOS_COMPILER==WIN32C
 	DWORD written;
diff --git a/scrsize.c b/scrsize.c
index 91fc03f250c2..c08d666704b5 100644
--- a/scrsize.c
+++ b/scrsize.c
@@ -45,11 +45,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-static int get_winsize(dpy, window, p_width, p_height)
-	Display *dpy;
-	Window window;
-	int *p_width;
-	int *p_height;
+static int get_winsize(Display *dpy, Window window, int *p_width, int *p_height)
 {
 	XWindowAttributes win_attributes;
 	XSizeHints hints;
@@ -79,9 +75,7 @@ static int get_winsize(dpy, window, p_width, p_height)
 	return 0;
 }
 
-int main(argc, argv)
-	int argc;
-	char *argv[];
+int main(int argc, char *argv[])
 {
 	char *cp;
 	Display *dpy;
diff --git a/search.c b/search.c
index e824acb4a3fc..cb302a94e411 100644
--- a/search.c
+++ b/search.c
@@ -121,10 +121,9 @@ static struct pattern_info filter_info;
  * Are there any uppercase letters in this string?
  */
 	static int
-is_ucase(str)
-	char *str;
+is_ucase(constant char *str)
 {
-	char *str_end = str + strlen(str);
+	constant char *str_end = str + strlen(str);
 	LWCHAR ch;
 
 	while (str < str_end)
@@ -140,15 +139,13 @@ is_ucase(str)
  * Compile and save a search pattern.
  */
 	static int
-set_pattern(info, pattern, search_type)
-	struct pattern_info *info;
-	char *pattern;
-	int search_type;
+set_pattern(struct pattern_info *info, char *pattern, int search_type)
 {
 #if !NO_REGEX
 	if (pattern == NULL)
 		CLEAR_PATTERN(info->compiled);
-	else if (compile_pattern(pattern, search_type, &info->compiled) < 0)
+	else if (compile_pattern(pattern, search_type,
+	    (void **)&info->compiled) < 0)
 		return -1;
 #endif
 	/* Pattern compiled successfully; save the text too. */
@@ -178,14 +175,13 @@ set_pattern(info, pattern, search_type)
  * Discard a saved pattern.
  */
 	static void
-clear_pattern(info)
-	struct pattern_info *info;
+clear_pattern(struct pattern_info *info)
 {
 	if (info->text != NULL)
 		free(info->text);
 	info->text = NULL;
 #if !NO_REGEX
-	uncompile_pattern(&info->compiled);
+	uncompile_pattern((void **)&info->compiled);
 #endif
 }
 
@@ -193,8 +189,7 @@ clear_pattern(info)
  * Initialize saved pattern to nothing.
  */
 	static void
-init_pattern(info)
-	struct pattern_info *info;
+init_pattern(struct pattern_info *info)
 {
 	CLEAR_PATTERN(info->compiled);
 	info->text = NULL;
@@ -205,7 +200,7 @@ init_pattern(info)
  * Initialize search variables.
  */
 	public void
-init_search()
+init_search(void)
 {
 	init_pattern(&search_info);
 	init_pattern(&filter_info);
@@ -215,7 +210,7 @@ init_search()
  * Determine which text conversions to perform before pattern matching.
  */
 	static int
-get_cvt_ops()
+get_cvt_ops(void)
 {
 	int ops = 0;
 	if (is_caseless || bs_mode == BS_SPECIAL)
@@ -239,8 +234,7 @@ get_cvt_ops()
  * Is there a previous (remembered) search pattern?
  */
 	static int
-prev_pattern(info)
-	struct pattern_info *info;
+prev_pattern(struct pattern_info *info)
 {
 #if !NO_REGEX
 	if ((info->search_type & SRCH_NO_REGEX) == 0)
@@ -256,8 +250,7 @@ prev_pattern(info)
  * If on==0, force all hilites off.
  */
 	public void
-repaint_hilite(on)
-	int on;
+repaint_hilite(int on)
 {
 	int slinenum;
 	POSITION pos;
@@ -298,7 +291,7 @@ repaint_hilite(on)
  * Clear the attn hilite.
  */
 	public void
-clear_attn()
+clear_attn(void)
 {
 	int slinenum;
 	POSITION old_start_attnpos;
@@ -345,7 +338,7 @@ clear_attn()
  * Hide search string highlighting.
  */
 	public void
-undo_search()
+undo_search(void)
 {
 	if (!prev_pattern(&search_info))
 	{
@@ -363,8 +356,7 @@ undo_search()
  * Clear the hilite list.
  */
 	public void
-clr_hlist(anchor)
-	struct hilite_tree *anchor;
+clr_hlist(struct hilite_tree *anchor)
 {
 	struct hilite_storage *hls;
 	struct hilite_storage *nexthls;
@@ -385,13 +377,13 @@ clr_hlist(anchor)
 }
 
 	public void
-clr_hilite()
+clr_hilite(void)
 {
 	clr_hlist(&hilite_anchor);
 }
 
 	public void
-clr_filter()
+clr_filter(void)
 {
 	clr_hlist(&filter_anchor);
 }
@@ -520,9 +512,7 @@ hlist_find(anchor, pos)
  * Should any characters in a specified range be highlighted?
  */
 	static int
-is_hilited_range(pos, epos)
-	POSITION pos;
-	POSITION epos;
+is_hilited_range(POSITION pos, POSITION epos)
 {
 	struct hilite_node *n = hlist_find(&hilite_anchor, pos);
 	return (n != NULL && (epos == NULL_POSITION || epos > n->r.hl_startpos));
@@ -532,8 +522,7 @@ is_hilited_range(pos, epos)
  * Is a line "filtered" -- that is, should it be hidden?
  */
 	public int
-is_filtered(pos)
-	POSITION pos;
+is_filtered(POSITION pos)
 {
 	struct hilite_node *n;
 
@@ -549,8 +538,7 @@ is_filtered(pos)
  * just return pos.
  */
 	public POSITION
-next_unfiltered(pos)
-	POSITION pos;
+next_unfiltered(POSITION pos)
 {
 	struct hilite_node *n;
 
@@ -571,8 +559,7 @@ next_unfiltered(pos)
  * we're filtered right to the beginning, otherwise just return pos.
  */
 	public POSITION
-prev_unfiltered(pos)
-	POSITION pos;
+prev_unfiltered(POSITION pos)
 {
 	struct hilite_node *n;
 
@@ -597,11 +584,7 @@ prev_unfiltered(pos)
  * If nohide is nonzero, don't consider hide_hilite.
  */
 	public int
-is_hilited(pos, epos, nohide, p_matches)
-	POSITION pos;
-	POSITION epos;
-	int nohide;
-	int *p_matches;
+is_hilited(POSITION pos, POSITION epos, int nohide, int *p_matches)
 {
 	int match;
 
@@ -647,8 +630,7 @@ is_hilited(pos, epos, nohide, p_matches)
  * capacity, or create a new one if not.
  */
 	static struct hilite_storage*
-hlist_getstorage(anchor)
-	struct hilite_tree *anchor;
+hlist_getstorage(struct hilite_tree *anchor)
 {
 	int capacity = 1;
 	struct hilite_storage *s;
@@ -678,8 +660,7 @@ hlist_getstorage(anchor)
  * tree.
  */
 	static struct hilite_node*
-hlist_getnode(anchor)
-	struct hilite_tree *anchor;
+hlist_getnode(struct hilite_tree *anchor)
 {
 	struct hilite_storage *s = hlist_getstorage(anchor);
 	return &s->nodes[s->used++];
@@ -689,9 +670,7 @@ hlist_getnode(anchor)
  * Rotate the tree left around a pivot node.
  */
 	static void
-hlist_rotate_left(anchor, n)
-	struct hilite_tree *anchor;
-	struct hilite_node *n;
+hlist_rotate_left(struct hilite_tree *anchor, struct hilite_node *n)
 {
 	struct hilite_node *np = n->parent;
 	struct hilite_node *nr = n->right;
@@ -720,9 +699,7 @@ hlist_rotate_left(anchor, n)
  * Rotate the tree right around a pivot node.
  */
 	static void
-hlist_rotate_right(anchor, n)
-	struct hilite_tree *anchor;
-	struct hilite_node *n;
+hlist_rotate_right(struct hilite_tree *anchor, struct hilite_node *n)
 {
 	struct hilite_node *np = n->parent;
 	struct hilite_node *nl = n->left;
@@ -752,9 +729,7 @@ hlist_rotate_right(anchor, n)
  * Add a new hilite to a hilite list.
  */
 	static void
-add_hilite(anchor, hl)
-	struct hilite_tree *anchor;
-	struct hilite *hl;
+add_hilite(struct hilite_tree *anchor, struct hilite *hl)
 {
 	struct hilite_node *p, *n, *u;
 
@@ -931,11 +906,7 @@ add_hilite(anchor, hl)
  * Hilight every character in a range of displayed characters.
  */
 	static void
-create_hilites(linepos, start_index, end_index, chpos)
-	POSITION linepos;
-	int start_index;
-	int end_index;
-	int *chpos;
+create_hilites(POSITION linepos, int start_index, int end_index, int *chpos)
 {
 	struct hilite hl;
 	int i;
@@ -972,14 +943,8 @@ create_hilites(linepos, start_index, end_index, chpos)
  * sp,ep delimit the first match already found.
  */
 	static void
-hilite_line(linepos, line, line_len, chpos, sp, ep, cvt_ops)
-	POSITION linepos;
-	char *line;
-	int line_len;
-	int *chpos;
-	char *sp;
-	char *ep;
-	int cvt_ops;
+hilite_line(POSITION linepos, char *line, int line_len, int *chpos, char *sp,
+    char *ep, int cvt_ops)
 {
 	char *searchp;
 	char *line_end = line + line_len;
@@ -1020,7 +985,7 @@ hilite_line(linepos, line, line_len, chpos, sp, ep, cvt_ops)
  * Updates the internal search state to reflect a change in the -i flag.
  */
 	public void
-chg_caseless()
+chg_caseless(void)
 {
 	if (!is_ucase_pattern)
 		/*
@@ -1041,7 +1006,7 @@ chg_caseless()
  * Find matching text which is currently on screen and highlight it.
  */
 	static void
-hilite_screen()
+hilite_screen(void)
 {
 	struct scrpos scrpos;
 
@@ -1056,7 +1021,7 @@ hilite_screen()
  * Change highlighting parameters.
  */
 	public void
-chg_hilite()
+chg_hilite(void)
 {
 	/*
 	 * Erase any highlights currently on screen.
@@ -1076,8 +1041,7 @@ chg_hilite()
  * Figure out where to start a search.
  */
 	static POSITION
-search_pos(search_type)
-	int search_type;
+search_pos(int search_type)
 {
 	POSITION pos;
 	int linenum;
@@ -1169,14 +1133,8 @@ search_pos(search_type)
  * Search a subset of the file, specified by start/end position.
  */
 	static int
-search_range(pos, endpos, search_type, matches, maxlines, plinepos, pendpos)
-	POSITION pos;
-	POSITION endpos;
-	int search_type;
-	int matches;
-	int maxlines;
-	POSITION *plinepos;
-	POSITION *pendpos;
+search_range(POSITION pos, POSITION endpos, int search_type, int matches,
+    int maxlines, POSITION *plinepos, POSITION *pendpos)
 {
 	char *line;
 	char *cline;
@@ -1355,8 +1313,7 @@ search_range(pos, endpos, search_type, matches, maxlines, plinepos, pendpos)
  * search for a pattern in history. If found, compile that pattern.
  */
 	static int 
-hist_pattern(search_type) 
-	int search_type;
+hist_pattern(int search_type)
 {
 #if CMD_HISTORY
 	char *pattern;
@@ -1390,10 +1347,7 @@ hist_pattern(search_type)
  * if less than n matches are found in this file.
  */
 	public int
-search(search_type, pattern, n)
-	int search_type;
-	char *pattern;
-	int n;
+search(int search_type, char *pattern, int n)
 {
 	POSITION pos;
 
@@ -1527,10 +1481,7 @@ search(search_type, pattern, n)
  * prep_hilite asks that the range (spos,epos) be covered by the prep region.
  */
 	public void
-prep_hilite(spos, epos, maxlines)
-	POSITION spos;
-	POSITION epos;
-	int maxlines;
+prep_hilite(POSITION spos, POSITION epos, int maxlines)
 {
 	POSITION nprep_startpos = prep_startpos;
 	POSITION nprep_endpos = prep_endpos;
@@ -1697,9 +1648,7 @@ prep_hilite(spos, epos, maxlines)
  * Set the pattern to be used for line filtering.
  */
 	public void
-set_filter_pattern(pattern, search_type)
-	char *pattern;
-	int search_type;
+set_filter_pattern(char *pattern, int search_type)
 {
 	clr_filter();
 	if (pattern == NULL || *pattern == '\0')
@@ -1713,7 +1662,7 @@ set_filter_pattern(pattern, search_type)
  * Is there a line filter in effect?
  */
 	public int
-is_filtering()
+is_filtering(void)
 {
 	if (ch_getflags() & CH_HELPFILE)
 		return (0);
diff --git a/signal.c b/signal.c
index 37a9793be49c..836946ce8986 100644
--- a/signal.c
+++ b/signal.c
@@ -40,8 +40,7 @@ extern long jump_sline_fraction;
  */
 	/* ARGSUSED*/
 	static RETSIGTYPE
-u_interrupt(type)
-	int type;
+u_interrupt(int type)
 {
 	bell();
 #if OS2
@@ -68,8 +67,7 @@ u_interrupt(type)
  */
 	/* ARGSUSED*/
 	static RETSIGTYPE
-stop(type)
-	int type;
+stop(int type)
 {
 	LSIGNAL(SIGTSTP, stop);
 	sigs |= S_STOP;
@@ -84,8 +82,7 @@ stop(type)
  */
 	/* ARGSUSED*/
 	public RETSIGTYPE
-winch(type)
-	int type;
+winch(int type)
 {
 	LSIGNAL(SIGWINCH, winch);
 	sigs |= S_WINCH;
@@ -99,8 +96,7 @@ winch(type)
  */
 	/* ARGSUSED*/
 	public RETSIGTYPE
-winch(type)
-	int type;
+winch(int type)
 {
 	LSIGNAL(SIGWIND, winch);
 	sigs |= S_WINCH;
@@ -117,8 +113,7 @@ winch(type)
 #include "windows.h"
 
 	static BOOL WINAPI 
-wbreak_handler(dwCtrlType)
-	DWORD dwCtrlType;
+wbreak_handler(DWORD dwCtrlType)
 {
 	switch (dwCtrlType)
 	{
@@ -137,8 +132,7 @@ wbreak_handler(dwCtrlType)
  * Set up the signal handlers.
  */
 	public void
-init_signals(on)
-	int on;
+init_signals(int on)
 {
 	if (on)
 	{
@@ -190,9 +184,9 @@ init_signals(on)
  * A received signal cause a bit to be set in "sigs".
  */
 	public void
-psignals()
+psignals(void)
 {
-	register int tsignals;
+	int tsignals;
 
 	if ((tsignals = sigs) == 0)
 		return;
diff --git a/tags.c b/tags.c
index 5acf3747b7e9..3fb65b0443f9 100644
--- a/tags.c
+++ b/tags.c
@@ -43,13 +43,13 @@ enum {
 	T_GPATH		/* 'GPATH': path name (global) */
 };
 
-static enum tag_result findctag();
-static enum tag_result findgtag();
-static char *nextgtag();
-static char *prevgtag();
-static POSITION ctagsearch();
-static POSITION gtagsearch();
-static int getentry();
+static enum tag_result findctag(char *tag);
+static enum tag_result findgtag(char *tag, int type);
+static char *nextgtag(void);
+static char *prevgtag(void);
+static POSITION ctagsearch(void);
+static POSITION gtagsearch(void);
+static int getentry(char *buf, char **tag, char **file, char **line);
 
 /*
  * The list of tags generated by the last findgtag() call.
@@ -88,9 +88,9 @@ static struct tag *curtag;
  * Delete tag structures.
  */
 	public void
-cleantags()
+cleantags(void)
 {
-	register struct tag *tp;
+	struct tag *tp;
 
 	/*
 	 * Delete any existing tag list.
@@ -110,14 +110,9 @@ cleantags()
  * Create a new tag entry.
  */
 	static struct tag *
-maketagent(name, file, linenum, pattern, endline)
-	char *name;
-	char *file;
-	LINENUM linenum;
-	char *pattern;
-	int endline;
+maketagent(char *name, char *file, LINENUM linenum, char *pattern, int endline)
 {
-	register struct tag *tp;
+	struct tag *tp;
 
 	tp = (struct tag *) ecalloc(sizeof(struct tag), 1);
 	tp->tag_file = (char *) ecalloc(strlen(file) + 1, sizeof(char));
@@ -138,7 +133,7 @@ maketagent(name, file, linenum, pattern, endline)
  * Get tag mode.
  */
 	public int
-gettagtype()
+gettagtype(void)
 {
 	int f;
 
@@ -169,8 +164,7 @@ gettagtype()
  * to find the tag.
  */
 	public void
-findtag(tag)
-	register char *tag;
+findtag(char *tag)
 {
 	int type = gettagtype();
 	enum tag_result result;
@@ -200,7 +194,7 @@ findtag(tag)
  * Search for a tag.
  */
 	public POSITION
-tagsearch()
+tagsearch(void)
 {
 	if (curtag == NULL)
 		return (NULL_POSITION);  /* No gtags loaded! */
@@ -214,8 +208,7 @@ tagsearch()
  * Go to the next tag.
  */
 	public char *
-nexttag(n)
-	int n;
+nexttag(int n)
 {
 	char *tagfile = (char *) NULL;
 
@@ -228,8 +221,7 @@ nexttag(n)
  * Go to the previous tag.
  */
 	public char *
-prevtag(n)
-	int n;
+prevtag(int n)
 {
 	char *tagfile = (char *) NULL;
 
@@ -242,7 +234,7 @@ prevtag(n)
  * Return the total number of tags.
  */
 	public int
-ntags()
+ntags(void)
 {
 	return total;
 }
@@ -251,7 +243,7 @@ ntags()
  * Return the sequence number of current tag.
  */
 	public int
-curr_tag()
+curr_tag(void)
 {
 	return curseq;
 }
@@ -265,12 +257,11 @@ curr_tag()
  * Sets curtag to the first tag entry.
  */
 	static enum tag_result
-findctag(tag)
-	register char *tag;
+findctag(char *tag)
 {
 	char *p;
-	register FILE *f;
-	register int taglen;
+	FILE *f;
+	int taglen;
 	LINENUM taglinenum;
 	char *tagfile;
 	char *tagpattern;
@@ -377,7 +368,7 @@ findctag(tag)
  * Edit current tagged file.
  */
 	public int
-edit_tagfile()
+edit_tagfile(void)
 {
 	if (curtag == NULL)
 		return (1);
@@ -394,7 +385,7 @@ edit_tagfile()
  *	parentheses (which are almost always found in a tag).
  */
 	static POSITION
-ctagsearch()
+ctagsearch(void)
 {
 	POSITION pos, linepos;
 	LINENUM linenum;
@@ -470,9 +461,7 @@ ctagsearch()
  * Sets curtag to the first tag entry.
  */
 	static enum tag_result
-findgtag(tag, type)
-	char *tag;		/* tag to load */
-	int type;		/* tags type */
+findgtag(char *tag, int type)
 {
 	char buf[256];
 	FILE *fp;
@@ -605,7 +594,7 @@ static int circular = 0;	/* 1: circular tag structure */
  * appropriate tag.
  */
 	static char *
-nextgtag()
+nextgtag(void)
 {
 	struct tag *tp;
 
@@ -635,7 +624,7 @@ nextgtag()
  * at the appropriate tag.
  */
 	static char *
-prevgtag()
+prevgtag(void)
 {
 	struct tag *tp;
 
@@ -665,7 +654,7 @@ prevgtag()
  * if it was unable to position at the tag, 0 if successful.
  */
 	static POSITION
-gtagsearch()
+gtagsearch(void)
 {
 	if (curtag == NULL)
 		return (NULL_POSITION);  /* No gtags loaded! */
@@ -701,11 +690,7 @@ gtagsearch()
  * into buf.
  */
 	static int
-getentry(buf, tag, file, line)
-	char *buf;	/* standard or extended ctags -x format data */
-	char **tag;	/* name of the tag we actually found */
-	char **file;	/* file in which to find this tag */
-	char **line;	/* line number of file where this tag is found */
+getentry(char *buf, char **tag, char **file, char **line)
 {
 	char *p = buf;
 
diff --git a/ttyin.c b/ttyin.c
index 129eea158b63..7a8364c8af5f 100644
--- a/ttyin.c
+++ b/ttyin.c
@@ -31,7 +31,7 @@ extern int utf_mode;
  * Open keyboard for input.
  */
 	public void
-open_getchr()
+open_getchr(void)
 {
 #if MSDOS_COMPILER==WIN32C
 	/* Need this to let child processes inherit our console handle */
@@ -85,7 +85,7 @@ open_getchr()
  * Close the keyboard.
  */
 	public void
-close_getchr()
+close_getchr(void)
 {
 #if MSDOS_COMPILER==WIN32C
 	SetConsoleMode((HANDLE)tty, console_mode);
@@ -97,7 +97,7 @@ close_getchr()
  * Get a character from the keyboard.
  */
 	public int
-getchr()
+getchr(void)
 {
 	char c;
 	int result;