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https://github.com/jart/cosmopolitan.git
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dd8c4dbd7d
There's now a much stronger level of assurance that signaling on Windows will be atomic, low-latency, low tail latency, and shall never deadlock.
38 lines
2.4 KiB
C
38 lines
2.4 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/calls/internal.h"
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#include "libc/calls/struct/sigset.internal.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#ifdef __x86_64__
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textwindows int sys_pause_nt(void) {
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int rc;
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// we don't strictly need to block signals, but it reduces signal
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// delivery latency, by preventing other threads from delivering a
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// signal asynchronously. it takes about ~5us to deliver a signal
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// using SetEvent() whereas it takes ~30us to use SuspendThread(),
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// GetThreadContext(), SetThreadContext(), and ResumeThread().
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BLOCK_SIGNALS;
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while (!(rc = _park_norestart(-1u, 0)))
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donothing;
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ALLOW_SIGNALS;
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return rc;
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}
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#endif /* __x86_64__ */
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