glibc/sysdeps/htl/sem-post.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

71 lines
1.9 KiB
C

/* Post a semaphore. Generic version.
Copyright (C) 2005-2022 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/>. */
#include <semaphore.h>
#include <assert.h>
#include <hurdlock.h>
#include <pt-internal.h>
int
__sem_post (sem_t *sem)
{
struct new_sem *isem = (struct new_sem *) sem;
int flags = isem->pshared ? GSYNC_SHARED : 0;
#if __HAVE_64B_ATOMICS
uint64_t d = atomic_load_relaxed (&isem->data);
do
{
if ((d & SEM_VALUE_MASK) == SEM_VALUE_MAX)
{
errno = EOVERFLOW;
return -1;
}
}
while (!atomic_compare_exchange_weak_release (&isem->data, &d, d + 1));
if ((d >> SEM_NWAITERS_SHIFT) != 0)
/* Wake one waiter. */
__lll_wake (((unsigned int *) &isem->data) + SEM_VALUE_OFFSET, flags);
#else
unsigned int v = atomic_load_relaxed (&isem->value);
do
{
if ((v >> SEM_VALUE_SHIFT) == SEM_VALUE_MAX)
{
errno = EOVERFLOW;
return -1;
}
}
while (!atomic_compare_exchange_weak_release
(&isem->value, &v, v + (1 << SEM_VALUE_SHIFT)));
if ((v & SEM_NWAITERS_MASK) != 0)
/* Wake one waiter. */
__lll_wake (&isem->value, flags);
#endif
return 0;
}
libpthread_hidden_def (__sem_post)
strong_alias (__sem_post, sem_post);