cosmopolitan/libc/intrin/pthread_attr_setstacksize.c
2022-09-07 05:28:32 -07:00

53 lines
3.1 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/errno.h"
#include "libc/intrin/pthread.h"
/**
* Sets size of thread stack.
*
* Your stack must have at least `PTHREAD_STACK_MIN` bytes, which
* Cosmpolitan Libc defines as `GetStackSize()`. It's a link-time
* constant used by Actually Portable Executable that's 128 kb by
* default. See libc/runtime/stack.h for docs on your stack limit
* since the APE ELF phdrs are the one true source of truth here.
*
* Cosmpolitan Libc runtime magic (e.g. ftrace) and memory safety
* (e.g. kprintf) assumes that stack sizes are two-powers and are
* aligned to that two-power. Conformance isn't required since we
* say caveat emptor to those who don't maintain these invariants
*
* Unlike pthread_attr_setstack() this function should be used if
* you want the Cosmopolitan Libc runtime to allocate a stack for
* you. Since the runtime uses mmap(MAP_STACK) to do that, you'll
* need to choose a multiple of FRAMESIZE, due to Windows.
*
* If this function isn't called it'll default to GetStackSize().
*
* @param x contains stack size in bytes
* @return 0 on success, or errno on error
* @raise EINVAL if `x` is less than `PTHREAD_STACK_MIN`
*/
int pthread_attr_setstacksize(pthread_attr_t *a, size_t x) {
if (x < PTHREAD_STACK_MIN) return EINVAL;
if (x & (FRAMESIZE - 1)) return EINVAL;
if (x < FRAMESIZE) return EINVAL;
a->stacksize = x;
return 0;
}