cosmopolitan/libc/thread/pthread_getattr_np.c
Justine Tunney 4a6fd3d910
Make more improvements to threading support
- fix rare thread exit race condition on openbsd
- pthread_getattr_np() now supplies detached status
- child threads may now pthread_join() the main thread
- introduce sigandset(), sigorset(), and sigisemptyset()
- introduce pthread_cleanup_push() and pthread_cleanup_pop()
2022-10-09 00:08:47 -07:00

66 lines
3.7 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 2022 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/intrin/atomic.h"
#include "libc/str/str.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
/**
* Gets thread attributes.
*
* These attributes are copied from the ones supplied when
* pthread_create() was called. However this function supplies
* additional runtime information too:
*
* 1. The detached state. You can use pthread_attr_getdetachstate() on
* the `attr` result to see, for example, if a thread detached itself
* or some other thread detached it, after it was spawned.
*
* 2. The thread's stack. You can use pthread_attr_getstack() to see the
* address and size of the stack that was allocated by cosmo for your
* thread. This is useful for knowing where the stack is. It can also
* be useful If you explicitly configured a stack too, since we might
* have needed to slightly tune the address and size to meet platform
* requirements. This function returns information that reflects that
*
* 3. You can view changes pthread_create() may have made to the stack
* guard size by calling pthread_attr_getguardsize() on `attr`
*
* @param attr is output argument that receives attributes, which should
* find its way to pthread_attr_destroy() when it's done being used
* @return 0 on success, or errno on error
* @raise ENOMEM is listed as a possible result by LSB 5.0
*/
int pthread_getattr_np(pthread_t thread, pthread_attr_t *attr) {
struct PosixThread *pt = (struct PosixThread *)thread;
memcpy(attr, &pt->attr, sizeof(pt->attr));
switch (atomic_load_explicit(&pt->status, memory_order_relaxed)) {
case kPosixThreadJoinable:
case kPosixThreadTerminated:
attr->__detachstate = PTHREAD_CREATE_JOINABLE;
break;
case kPosixThreadDetached:
case kPosixThreadZombie:
attr->__detachstate = PTHREAD_CREATE_DETACHED;
break;
default:
unreachable;
}
return 0;
}