glibc/sysdeps/posix/flock.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

57 lines
1.7 KiB
C

/* Copyright (C) 1992-2022 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* 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 <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/file.h>
/* Apply or remove an advisory lock, according to OPERATION,
on the file FD refers to. */
int
__flock (int fd, 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:
__set_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)