1 files changed, 14 insertions, 1 deletions

diff --git a/lib/libc/stdio/putchar.c b/lib/libc/stdio/putchar.c
index 036b8970772c..5e04a6c72f2c 100644
--- a/lib/libc/stdio/putchar.c
+++ b/lib/libc/stdio/putchar.c
@@ -39,16 +39,29 @@ static char sccsid[] = "@(#)putchar.c	8.1 (Berkeley) 6/4/93";
 #endif /* LIBC_SCCS and not lint */
 
 #include <stdio.h>
+#ifdef _THREAD_SAFE
+#include <pthread.h>
+#include "pthread_private.h"
+#endif
 
 #undef putchar
 
 /*
  * A subroutine version of the macro putchar
  */
+int
 putchar(c)
 	int c;
 {
+	int retval;
 	register FILE *so = stdout;
 
-	return (__sputc(c, so));
+#ifdef _THREAD_SAFE
+	_thread_flockfile(so,__FILE__,__LINE__);
+#endif
+	retval = __sputc(c, so);
+#ifdef _THREAD_SAFE
+	_thread_funlockfile(so);
+#endif
+	return (retval);
 }