From 28f540f45bbacd939bfd07f213bcad2bf730b1bf Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 18 Feb 1995 01:27:10 +0000 Subject: initial import --- sysdeps/posix/flock.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 sysdeps/posix/flock.c (limited to 'sysdeps/posix/flock.c') diff --git a/sysdeps/posix/flock.c b/sysdeps/posix/flock.c new file mode 100644 index 0000000000..b4c9fc3b79 --- /dev/null +++ b/sysdeps/posix/flock.c @@ -0,0 +1,58 @@ +/* Copyright (C) 1992, 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* This file implements the `flock' function in terms of the POSIX.1 `fcntl' + locking mechanism. In 4BSD, these are two incompatible locking mechanisms, + perhaps with different semantics? */ + +#include +#include +#include +#include +#include + +/* Apply or remove an advisory lock, according to OPERATION, + on the file FD refers to. */ +int +DEFUN(__flock, (fd, operation), int fd AND int operation) +{ + struct flock lbuf; + + switch (operation & ~LOCK_NB) + { + case LOCK_SH: + lbuf.l_type = F_RDLCK; + break; + case LOCK_EX: + lbuf.l_type = F_WRLCK; + break; + case LOCK_UN: + lbuf.l_type = F_UNLCK; + break; + default: + errno = EINVAL; + return -1; + } + + lbuf.l_whence = SEEK_SET; + lbuf.l_start = lbuf.l_len = 0L; /* Lock the whole file. */ + + return __fcntl (fd, (operation & LOCK_NB) ? F_SETLK : F_SETLKW, &lbuf); +} + +weak_alias (__flock, flock) -- cgit v1.2.3