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https://github.com/jart/cosmopolitan.git
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e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
58 lines
2.7 KiB
C
58 lines
2.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/atomic.h"
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#include "libc/limits.h"
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#include "libc/runtime/syslib.internal.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/semaphore.h"
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#include "third_party/nsync/futex.internal.h"
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/**
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* Unlocks semaphore.
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*
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* @return 0 on success, or -1 w/ errno
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* @raise EINVAL if `sem` isn't valid
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*/
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int sem_post(sem_t *sem) {
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int rc, old, wakeups;
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#if 0
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if (IsXnuSilicon() && sem->sem_magic == SEM_MAGIC_KERNEL) {
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return _sysret(__syslib->__sem_post(sem->sem_kernel));
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}
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#endif
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old = atomic_fetch_add_explicit(&sem->sem_value, 1, memory_order_acq_rel);
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unassert(old > INT_MIN);
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if (old >= 0) {
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wakeups = nsync_futex_wake_(&sem->sem_value, 1, true);
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npassert(wakeups >= 0);
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rc = 0;
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} else {
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wakeups = 0;
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rc = einval();
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}
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return rc;
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}
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