1/* Copyright (C) 2002-2020 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include "pthreadP.h"
21#include <atomic.h>
22
23
24int
25__pthread_key_create (pthread_key_t *key, void (*destr) (void *))
26{
27 /* Find a slot in __pthread_keys which is unused. */
28 for (size_t cnt = 0; cnt < PTHREAD_KEYS_MAX; ++cnt)
29 {
30 uintptr_t seq = __pthread_keys[cnt].seq;
31
32 if (KEY_UNUSED (seq) && KEY_USABLE (seq)
33 /* We found an unused slot. Try to allocate it. */
34 && ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[cnt].seq,
35 seq + 1, seq))
36 {
37 /* Remember the destructor. */
38 __pthread_keys[cnt].destr = destr;
39
40 /* Return the key to the caller. */
41 *key = cnt;
42
43 /* The call succeeded. */
44 return 0;
45 }
46 }
47
48 return EAGAIN;
49}
50weak_alias (__pthread_key_create, pthread_key_create)
51hidden_def (__pthread_key_create)
52