glibc/nptl/pthread_key_create.c

52 lines
1.6 KiB
C

/* Copyright (C) 2002-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include "pthreadP.h"
#include <atomic.h>
int
__pthread_key_create (pthread_key_t *key, void (*destr) (void *))
{
/* Find a slot in __pthread_keys which is unused. */
for (size_t cnt = 0; cnt < PTHREAD_KEYS_MAX; ++cnt)
{
uintptr_t seq = __pthread_keys[cnt].seq;
if (KEY_UNUSED (seq) && KEY_USABLE (seq)
/* We found an unused slot. Try to allocate it. */
&& ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[cnt].seq,
seq + 1, seq))
{
/* Remember the destructor. */
__pthread_keys[cnt].destr = destr;
/* Return the key to the caller. */
*key = cnt;
/* The call succeeded. */
return 0;
}
}
return EAGAIN;
}
weak_alias (__pthread_key_create, pthread_key_create)
hidden_def (__pthread_key_create)