cosmopolitan/libc/intrin/gettid.c
Justine Tunney c995838e5c
Make improvements
- Clean up sigaction() code
- Add a port scanner example
- Introduce a ParseCidr() API
- Clean up our futex abstraction code
- Fix a harmless integer overflow in ParseIp()
- Use kernel semaphores on NetBSD to make threads much faster
2022-11-07 02:26:06 -08:00

47 lines
2.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/likely.h"
#include "libc/thread/tls.h"
/**
* Returns current thread id.
*
* On Linux, and Linux only, this is guaranteed to be equal to getpid()
* if this is the main thread. On NetBSD, gettid() for the main thread
* is always 1.
*
* @return thread id greater than zero or -1 w/ errno
* @asyncsignalsafe
* @threadsafe
* @vforksafe
*/
int gettid(void) {
int tid;
if (VERY_LIKELY(__tls_enabled && !__vforked)) {
tid = atomic_load_explicit(&__get_tls()->tib_tid, memory_order_acquire);
if (VERY_LIKELY(tid > 0)) {
return tid;
}
}
return sys_gettid();
}