/[pcsx2_0.9.7]/trunk/3rdparty/w32pthreads/ptw32_semwait.c
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Contents of /trunk/3rdparty/w32pthreads/ptw32_semwait.c

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Revision 31 - (show annotations) (download)
Tue Sep 7 03:24:11 2010 UTC (9 years, 11 months ago) by william
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committing r3113 initial commit again...
1 /*
2 * ptw32_semwait.c
3 *
4 * Description:
5 * This translation unit implements mutual exclusion (mutex) primitives.
6 *
7 * --------------------------------------------------------------------------
8 *
9 * Pthreads-win32 - POSIX Threads Library for Win32
10 * Copyright(C) 1998 John E. Bossom
11 * Copyright(C) 1999,2005 Pthreads-win32 contributors
12 *
13 * Contact Email: rpj@callisto.canberra.edu.au
14 *
15 * The current list of contributors is contained
16 * in the file CONTRIBUTORS included with the source
17 * code distribution. The list can also be seen at the
18 * following World Wide Web location:
19 * http://sources.redhat.com/pthreads-win32/contributors.html
20 *
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Lesser General Public
23 * License as published by the Free Software Foundation; either
24 * version 2 of the License, or (at your option) any later version.
25 *
26 * This library is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
29 * Lesser General Public License for more details.
30 *
31 * You should have received a copy of the GNU Lesser General Public
32 * License along with this library in the file COPYING.LIB;
33 * if not, write to the Free Software Foundation, Inc.,
34 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
35 */
36
37 #include "ptw32pch.h"
38
39
40 int
41 ptw32_semwait (sem_t * sem)
42 /*
43 * ------------------------------------------------------
44 * DESCRIPTION
45 * This function waits on a POSIX semaphore. If the
46 * semaphore value is greater than zero, it decreases
47 * its value by one. If the semaphore value is zero, then
48 * the calling thread (or process) is blocked until it can
49 * successfully decrease the value.
50 *
51 * Unlike sem_wait(), this routine is non-cancelable.
52 *
53 * RESULTS
54 * 0 successfully decreased semaphore,
55 * -1 failed, error in errno.
56 * ERRNO
57 * EINVAL 'sem' is not a valid semaphore,
58 * ENOSYS semaphores are not supported,
59 * EINTR the function was interrupted by a signal,
60 * EDEADLK a deadlock condition was detected.
61 *
62 * ------------------------------------------------------
63 */
64 {
65 int result = 0;
66 sem_t s = *sem;
67
68 if (s == NULL)
69 {
70 result = EINVAL;
71 }
72 else
73 {
74 if ((result = pthread_mutex_lock (&s->lock)) == 0)
75 {
76 int v = --s->value;
77
78 (void) pthread_mutex_unlock (&s->lock);
79
80 if (v < 0)
81 {
82 /* Must wait */
83 if (WaitForSingleObject (s->sem, INFINITE) == WAIT_OBJECT_0)
84 {
85 #ifdef NEED_SEM
86 if (pthread_mutex_lock (&s->lock) == 0)
87 {
88 if (s->leftToUnblock > 0)
89 {
90 --s->leftToUnblock;
91 SetEvent(s->sem);
92 }
93 (void) pthread_mutex_unlock (&s->lock);
94 }
95 #endif
96 return 0;
97 }
98 }
99 else
100 {
101 return 0;
102 }
103 }
104 }
105
106 if (result != 0)
107 {
108 errno = result;
109 return -1;
110 }
111
112 return 0;
113
114 } /* ptw32_semwait */

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