This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
SDL_syssem.c
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2009 Sam Lantinga
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
This 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.
This 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 this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
22
#include "SDL_config.h"
23
24
25
26
27
28
29
30
31
#include <pthread.h>
#include <semaphore.h>
#include "SDL_thread.h"
#include "SDL_timer.h"
/* Wrapper around POSIX 1003.1b semaphores */
32
#if defined(__MACOSX__) || defined(__IPHONEOS__)
33
34
35
/* Mac OS X doesn't support sem_getvalue() as of version 10.4 */
#include "../generic/SDL_syssem.c"
#else
37
38
39
struct SDL_semaphore
{
sem_t sem;
40
41
42
};
/* Create a semaphore, initialized with value */
43
44
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
46
47
48
49
50
51
52
53
54
55
56
SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem));
if (sem) {
if (sem_init(&sem->sem, 0, initial_value) < 0) {
SDL_SetError("sem_init() failed");
SDL_free(sem);
sem = NULL;
}
} else {
SDL_OutOfMemory();
}
return sem;
59
60
void
SDL_DestroySemaphore(SDL_sem * sem)
62
63
64
65
if (sem) {
sem_destroy(&sem->sem);
SDL_free(sem);
}
68
69
int
SDL_SemTryWait(SDL_sem * sem)
71
72
73
74
75
76
77
78
79
80
81
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = SDL_MUTEX_TIMEDOUT;
if (sem_trywait(&sem->sem) == 0) {
retval = 0;
}
return retval;
84
85
int
SDL_SemWait(SDL_sem * sem)
87
88
89
90
91
92
93
94
95
96
97
98
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = sem_wait(&sem->sem);
if (retval < 0) {
SDL_SetError("sem_wait() failed");
}
return retval;
101
102
int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
/* Try the easy cases first */
if (timeout == 0) {
return SDL_SemTryWait(sem);
}
if (timeout == SDL_MUTEX_MAXWAIT) {
return SDL_SemWait(sem);
}
/* Ack! We have to busy wait... */
/* FIXME: Use sem_timedwait()? */
timeout += SDL_GetTicks();
do {
retval = SDL_SemTryWait(sem);
if (retval == 0) {
break;
}
SDL_Delay(1);
128
} while (SDL_GetTicks() < timeout);
129
130
return retval;
133
134
Uint32
SDL_SemValue(SDL_sem * sem)
136
137
138
139
140
141
142
143
int ret = 0;
if (sem) {
sem_getvalue(&sem->sem, &ret);
if (ret < 0) {
ret = 0;
}
}
return (Uint32) ret;
146
147
int
SDL_SemPost(SDL_sem * sem)
149
150
151
152
153
154
155
156
157
158
159
160
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = sem_post(&sem->sem);
if (retval < 0) {
SDL_SetError("sem_post() failed");
}
return retval;
162
163
#endif /* __MACOSX__ */
164
/* vi: set ts=4 sw=4 expandtab: */