1 /* Copyright (C) 2008, 2009 Free Software Foundation, Inc.
2    Contributed by Jakub Jelinek <jakub@redhat.com>.
3 
4    This file is part of the GNU OpenMP Library (libgomp).
5 
6    Libgomp is free software; you can redistribute it and/or modify it
7    under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3, or (at your option)
9    any later version.
10 
11    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14    more details.
15 
16    Under Section 7 of GPL version 3, you are granted additional
17    permissions described in the GCC Runtime Library Exception, version
18    3.1, as published by the Free Software Foundation.
19 
20    You should have received a copy of the GNU General Public License and
21    a copy of the GCC Runtime Library Exception along with this program;
22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23    <http://www.gnu.org/licenses/>.  */
24 
25 /* This is a Linux specific implementation of a mutex synchronization
26    mechanism for libgomp.  This type is private to the library.  This
27    implementation uses atomic instructions and the futex syscall.  */
28 
29 #ifndef GOMP_PTRLOCK_H
30 #define GOMP_PTRLOCK_H 1
31 
32 typedef struct { void *ptr; gomp_mutex_t lock; } gomp_ptrlock_t;
33 
34 static inline void gomp_ptrlock_init (gomp_ptrlock_t *ptrlock, void *ptr)
35 {
36   ptrlock->ptr = ptr;
37   gomp_mutex_init (&ptrlock->lock);
38 }
39 
40 static inline void *gomp_ptrlock_get (gomp_ptrlock_t *ptrlock)
41 {
42   if (ptrlock->ptr != NULL)
43     return ptrlock->ptr;
44 
45   gomp_mutex_lock (&ptrlock->lock);
46   if (ptrlock->ptr != NULL)
47     {
48       gomp_mutex_unlock (&ptrlock->lock);
49       return ptrlock->ptr;
50     }
51 
52   return NULL;
53 }
54 
55 static inline void gomp_ptrlock_set (gomp_ptrlock_t *ptrlock, void *ptr)
56 {
57   ptrlock->ptr = ptr;
58   gomp_mutex_unlock (&ptrlock->lock);
59 }
60 
61 static inline void gomp_ptrlock_destroy (gomp_ptrlock_t *ptrlock)
62 {
63   gomp_mutex_destroy (&ptrlock->lock);
64 }
65 
66 #endif /* GOMP_PTRLOCK_H */
67