From 87092eb3737a12bab804799042be8a6af704e9ba Mon Sep 17 00:00:00 2001
From: tjr <tjr@FreeBSD.org>
Date: Fri, 10 Jan 2003 05:34:11 +0000
Subject: Add a manual page for flockfile(), ftrylockfile(), and funlockfile().

---
 lib/libc/stdio/Makefile.inc |   4 +-
 lib/libc/stdio/flockfile.3  | 103 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+), 1 deletion(-)
 create mode 100644 lib/libc/stdio/flockfile.3

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 .
-- 
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