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comparison src/thread/pthread/SDL_syssem.c @ 1627:aee7ea396f59

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Fixed bug #179 SDL_SemValue() always returns 0. That's because the underlying POSIX sem_getvalue() is implemented as a noop in Mac OS X. Apart from that, semaphores do work properly (at least according to test/testsem), so I'm not sure if this is worth fixing at all.
author Sam Lantinga <slouken@libsdl.org>
date Thu, 13 Apr 2006 14:04:13 +0000
parents dc6b59e925a2
children eba962f9d603
comparison
equal deleted inserted replaced
1626:a80e1e0880b8 1627:aee7ea396f59
28 #include "SDL_timer.h" 28 #include "SDL_timer.h"
29 29
30 /* Wrapper around POSIX 1003.1b semaphores */ 30 /* Wrapper around POSIX 1003.1b semaphores */
31 31
32 #ifdef __MACOSX__ 32 #ifdef __MACOSX__
33 #define USE_NAMED_SEMAPHORES 1 33 /* Mac OS X doesn't support sem_getvalue() as of version 10.4 */
34 #include <unistd.h> 34 #include "../generic/SDL_syssem.c"
35 #endif 35 #else
36 36
37 struct SDL_semaphore { 37 struct SDL_semaphore {
38 sem_t *sem; 38 sem_t *sem;
39 #if !USE_NAMED_SEMAPHORES
40 sem_t sem_data;
41 #endif
42 }; 39 };
43 40
44 /* Create a semaphore, initialized with value */ 41 /* Create a semaphore, initialized with value */
45 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) 42 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
46 { 43 {
47 SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem)); 44 SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem));
48 if ( sem ) { 45 if ( sem ) {
49 #if USE_NAMED_SEMAPHORES
50 static int semnum = 0;
51 char name[32];
52
53 SDL_snprintf(name, SDL_arraysize(name), "/SDL_sem-%d-%4.4d", getpid(), semnum++);
54 sem->sem = sem_open(name, O_CREAT, 0600, initial_value);
55 if ( sem->sem == (sem_t *)SEM_FAILED ) {
56 SDL_SetError("sem_open(%s) failed", name);
57 SDL_free(sem);
58 sem = NULL;
59 } else {
60 sem_unlink(name);
61 }
62 #else
63 if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) { 46 if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) {
64 SDL_SetError("sem_init() failed"); 47 SDL_SetError("sem_init() failed");
65 SDL_free(sem); 48 SDL_free(sem);
66 sem = NULL; 49 sem = NULL;
67 } else { 50 } else {
68 sem->sem = &sem->sem_data; 51 sem->sem = &sem->sem_data;
69 } 52 }
70 #endif /* USE_NAMED_SEMAPHORES */
71 } else { 53 } else {
72 SDL_OutOfMemory(); 54 SDL_OutOfMemory();
73 } 55 }
74 return sem; 56 return sem;
75 } 57 }
76 58
77 void SDL_DestroySemaphore(SDL_sem *sem) 59 void SDL_DestroySemaphore(SDL_sem *sem)
78 { 60 {
79 if ( sem ) { 61 if ( sem ) {
80 #if USE_NAMED_SEMAPHORES
81 sem_close(sem->sem);
82 #else
83 sem_destroy(sem->sem); 62 sem_destroy(sem->sem);
84 #endif
85 SDL_free(sem); 63 SDL_free(sem);
86 } 64 }
87 } 65 }
88 66
89 int SDL_SemTryWait(SDL_sem *sem) 67 int SDL_SemTryWait(SDL_sem *sem)
133 if ( timeout == SDL_MUTEX_MAXWAIT ) { 111 if ( timeout == SDL_MUTEX_MAXWAIT ) {
134 return SDL_SemWait(sem); 112 return SDL_SemWait(sem);
135 } 113 }
136 114
137 /* Ack! We have to busy wait... */ 115 /* Ack! We have to busy wait... */
116 /* FIXME: Use sem_timedwait()? */
138 timeout += SDL_GetTicks(); 117 timeout += SDL_GetTicks();
139 do { 118 do {
140 retval = SDL_SemTryWait(sem); 119 retval = SDL_SemTryWait(sem);
141 if ( retval == 0 ) { 120 if ( retval == 0 ) {
142 break; 121 break;
172 if ( retval < 0 ) { 151 if ( retval < 0 ) {
173 SDL_SetError("sem_post() failed"); 152 SDL_SetError("sem_post() failed");
174 } 153 }
175 return retval; 154 return retval;
176 } 155 }
156
157 #endif /* __MACOSX__ */