diff options
| -rw-r--r-- | lib/libc/stdio/Makefile.inc | 4 | ||||
| -rw-r--r-- | lib/libc/stdio/flockfile.3 | 103 |
2 files changed, 106 insertions, 1 deletions
diff --git a/lib/libc/stdio/Makefile.inc b/lib/libc/stdio/Makefile.inc index 74db5e3..2b80ef7 100644 --- a/lib/libc/stdio/Makefile.inc +++ b/lib/libc/stdio/Makefile.inc @@ -22,7 +22,8 @@ SRCS+= _flock_stub.c asprintf.c clrerr.c fclose.c fdopen.c feof.c ferror.c \ vswprintf.c vswscanf.c vwprintf.c vwscanf.c wbuf.c wprintf.c wscanf.c \ wsetup.c -MAN+= fclose.3 ferror.3 fflush.3 fgetln.3 fgets.3 fgetws.3 fopen.3 fputs.3 \ +MAN+= fclose.3 ferror.3 fflush.3 fgetln.3 fgets.3 fgetws.3 flockfile.3 \ + fopen.3 fputs.3 \ fputws.3 fread.3 fseek.3 funopen.3 fwide.3 getc.3 getwc.3 mktemp.3 \ printf.3 putc.3 putwc.3 remove.3 scanf.3 setbuf.3 stdio.3 tmpnam.3 \ ungetc.3 ungetwc.3 wprintf.3 wscanf.3 @@ -30,6 +31,7 @@ MAN+= fclose.3 ferror.3 fflush.3 fgetln.3 fgets.3 fgetws.3 fopen.3 fputs.3 \ MLINKS+=ferror.3 clearerr.3 ferror.3 feof.3 ferror.3 fileno.3 MLINKS+=fflush.3 fpurge.3 MLINKS+=fgets.3 gets.3 +MLINKS+=flockfile.3 ftrylockfile.3 flockfile.3 funlockfile.3 MLINKS+=fopen.3 fdopen.3 fopen.3 freopen.3 MLINKS+=fputs.3 puts.3 MLINKS+=fread.3 fwrite.3 diff --git a/lib/libc/stdio/flockfile.3 b/lib/libc/stdio/flockfile.3 new file mode 100644 index 0000000..efbe233 --- /dev/null +++ b/lib/libc/stdio/flockfile.3 @@ -0,0 +1,103 @@ +.\" Copyright (c) 2003 Tim J. Robbins +.\" All rights reserved. +.\" +.\" 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. +.\" +.\" $FreeBSD$ +.\" +.Dd January 10, 2003 +.Dt FLOCKFILE 3 +.Os +.Sh NAME +.Nm flockfile , +.Nm ftrylockfile , +.Nm funlockfile +.Nd "stdio locking functions" +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In stdio.h +.Ft void +.Fn flockfile "FILE *stream" +.Ft int +.Fn ftrylockfile "FILE *stream" +.Ft void +.Fn funlockfile "FILE *stream" +.Sh DESCRIPTION +These functions provide explicit application-level locking of stdio streams. +They can be used to avoid output from multiple threads being interspersed, +input being dispersed among multiplte readers, and to avoid the overhead +of locking the stream for each operation. +.Pp +The +.Fn flockfile +function acquires an exclusive lock on the specified stream. +If another thread has already locked the stream, +.Fn flockfile +will block until the lock is released. +.Pp +The +.Fn ftrylockfile +function is a non-blocking version of +.Fn flockfile ; +if the lock cannot be acquired immediately, +.Fn ftrylockfile +returns non-zero instead of blocking. +.Pp +The +.Fn funlockfile +function releases the lock on a stream acquired by an earlier call to +.Fn flockfile +or +.Fn ftrylockfile . +.Pp +These functions behave as if there is a lock count associated +with each stream. +Each time +.Fn flockfile +is called on the stream, the count is incremented, +and each time +.Fn funlockfile +is called on the stream, the count is decremented. +The lock is only actually released when the count reaches zero. +.Sh RETURN VALUES +The +.Fn flockfile +and +.Fn funlockfile +functions return no value. +.Pp +The +.Fn ftrylockfile +returns zero if the stream was successfully locked, +non-zero otherwise. +.Sh SEE ALSO +.Xr getc_unlocked 3 , +.Xr putc_unlocked 3 +.Sh STANDARDS +The +.Fn flockfile , +.Fn ftrylockfile +and +.Fn funlockfile +functions conform to +.St -p1003.1-2001 . |
