diff options
author | Rodney W. Grimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
---|---|---|
committer | Rodney W. Grimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
commit | 58f0484fa251c266ede97b591b499fe3dd4f578e (patch) | |
tree | 41932a7161f4cd72005330a9c69747e7bab2ee5b /lib/libc/stdio/funopen.3 | |
parent | fb49e767ba942f74b1cee8814e085e5f2615ac53 (diff) | |
download | src-58f0484fa251c266ede97b591b499fe3dd4f578e.tar.gz src-58f0484fa251c266ede97b591b499fe3dd4f578e.zip |
Notes
Diffstat (limited to 'lib/libc/stdio/funopen.3')
-rw-r--r-- | lib/libc/stdio/funopen.3 | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/lib/libc/stdio/funopen.3 b/lib/libc/stdio/funopen.3 new file mode 100644 index 000000000000..8ed9b3074a2b --- /dev/null +++ b/lib/libc/stdio/funopen.3 @@ -0,0 +1,168 @@ +.\" Copyright (c) 1990, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Chris Torek. +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)funopen.3 8.1 (Berkeley) 6/9/93 +.\" +.Dd June 9, 1993 +.Dt FUNOPEN 3 +.Os +.Sh NAME +.Nm funopen , +.Nm fropen , +.Nm fwopen +.Nd open a stream +.Sh SYNOPSIS +.Fd #include <stdio.h> +.Ft FILE * +.Fn funopen "void *cookie" "int (*readfn)(void *, char *, int)" "int (writefn*)(void *, const char *, int)" "fpos_t (seekfn*)(void *, fpos_t, int)" "int (closefn*)(void *)" +.Ft FILE * +.Fn fropen "void *cookie" "int (*readfn)(void *, char *, int)" +.Ft FILE * +.Fn fwopen "void *cookie" "int (*writefn)(void *, char *, int)" +.Sh DESCRIPTION +The +.Fn funopen +function +associates a stream with up to four +.Dq Tn I/O No functions . +Either +.Fa readfn +or +.Fa writefn +must be specified; +the others can be given as an appropriately-typed +.Dv NULL +pointer. +These +.Tn I/O +functions will be used to read, write, seek and +close the new stream. +.Pp +In general, omitting a function means that any attempt to perform the +associated operation on the resulting stream will fail. +If the close function is omitted, closing the stream will flush +any buffered output and then succeed. +.Pp +The calling conventions of +.Fa readfn , +.Fa writefn , +.Fa seekfn +and +.Fa closefn +must match those, respectively, of +.Xr read 2 , +.Xr write 2 , +.Xr seek 2 , +and +.Xr close 2 +with the single exception that they are passed the +.Fa cookie +argument specified to +.Fn funopen +in place of the traditional file descriptor argument. +.Pp +Read and write +.Tn I/O +functions are allowed to change the underlying buffer +on fully buffered or line buffered streams by calling +.Xr setvbuf 3 . +They are also not required to completely fill or empty the buffer. +They are not, however, allowed to change streams from unbuffered to buffered +or to change the state of the line buffering flag. +They must also be prepared to have read or write calls occur on buffers other +than the one most recently specified. +.Pp +All user +.Tn I/O +functions can report an error by returning \-1. +Additionally, all of the functions should set the external variable +.Va errno +appropriately if an error occurs. +.Pp +An error on +.Fn closefn +does not keep the stream open. +.Pp +As a convenience, the include file +.Aq Pa stdio.h +defines the macros +.Fn fropen +and +.Fn fwopen +as calls to +.Fn funopen +with only a read or write function specified. +.Sh RETURN VALUES +Upon successful completion, +.Fn funopen +returns a +.Dv FILE +pointer. +Otherwise, +.Dv NULL +is returned and the global variable +.Va errno +is set to indicate the error. +.Sh ERRORS +.Bl -tag -width [EINVAL] +.It Bq Er EINVAL +The +.Fn funopen +function +was called without either a read or write function. +The +.Fn funopen +function +may also fail and set +.Va errno +for any of the errors +specified for the routine +.Xr malloc 3 . +.El +.Sh SEE ALSO +.Xr fcntl 2 , +.Xr open 2 , +.Xr fclose 3 , +.Xr fopen 3 , +.Xr fseek 3 , +.Xr setbuf 3 +.Sh HISTORY +The +.Fn funopen +functions first appeared in 4.4BSD. +.Sh BUGS +The +.Fn funopen +function +may not be portable to systems other than +.Bx . |