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comparison Python/thread_pthread.h @ 4994:9bc652e9f2b4 legacy-trunk

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Working semaphore implementation by Sjoerd.
author Guido van Rossum <guido@python.org>
date Fri, 17 Jan 1997 21:06:41 +0000
parents 65d2d8e67da3
children 2c81d7d68ed3
comparison
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4993:b82d847b3dcb 4994:9bc652e9f2b4
261 } 261 }
262 262
263 /* 263 /*
264 * Semaphore support. 264 * Semaphore support.
265 */ 265 */
266 /* NOTE: 100% non-functional at this time - tim */ 266
267 struct semaphore {
268 pthread_mutex_t mutex;
269 pthread_cond_t cond;
270 int value;
271 };
267 272
268 type_sema allocate_sema _P1(value, int value) 273 type_sema allocate_sema _P1(value, int value)
269 { 274 {
270 char *sema = 0; 275 struct semaphore *sema;
276 int status, error = 0;
277
271 dprintf(("allocate_sema called\n")); 278 dprintf(("allocate_sema called\n"));
272 if (!initialized) 279 if (!initialized)
273 init_thread(); 280 init_thread();
274 281
282 sema = (struct semaphore *) malloc(sizeof(struct semaphore));
283 if (sema != NULL) {
284 sema->value = value;
285 status = pthread_mutex_init(&sema->mutex,
286 pthread_mutexattr_default);
287 CHECK_STATUS("pthread_mutex_init");
288 status = pthread_cond_init(&sema->cond,
289 pthread_condattr_default);
290 CHECK_STATUS("pthread_cond_init");
291 if (error) {
292 free((void *) sema);
293 sema = NULL;
294 }
295 }
275 dprintf(("allocate_sema() -> %lx\n", (long) sema)); 296 dprintf(("allocate_sema() -> %lx\n", (long) sema));
276 return (type_sema) sema; 297 return (type_sema) sema;
277 } 298 }
278 299
279 void free_sema _P1(sema, type_sema sema) 300 void free_sema _P1(sema, type_sema sema)
280 { 301 {
302 int status, error = 0;
303 struct semaphore *thesema = (struct semaphore *) sema;
304
281 dprintf(("free_sema(%lx) called\n", (long) sema)); 305 dprintf(("free_sema(%lx) called\n", (long) sema));
306 status = pthread_cond_destroy(&thesema->cond);
307 CHECK_STATUS("pthread_cond_destroy");
308 status = pthread_mutex_destroy(&thesema->mutex);
309 CHECK_STATUS("pthread_mutex_destroy");
310 free((void *) thesema);
282 } 311 }
283 312
284 int down_sema _P2(sema, type_sema sema, waitflag, int waitflag) 313 int down_sema _P2(sema, type_sema sema, waitflag, int waitflag)
285 { 314 {
315 int status, error = 0, success;
316 struct semaphore *thesema = (struct semaphore *) sema;
317
286 dprintf(("down_sema(%lx, %d) called\n", (long) sema, waitflag)); 318 dprintf(("down_sema(%lx, %d) called\n", (long) sema, waitflag));
319 status = pthread_mutex_lock(&thesema->mutex);
320 CHECK_STATUS("pthread_mutex_lock");
321 if (waitflag) {
322 while (!error && thesema->value <= 0) {
323 status = pthread_cond_wait(&thesema->cond,
324 &thesema->mutex);
325 CHECK_STATUS("pthread_cond_wait");
326 }
327 }
328 if (error)
329 success = 0;
330 else if (thesema->value > 0) {
331 thesema->value--;
332 success = 1;
333 }
334 else
335 success = 0;
336 status = pthread_mutex_unlock(&thesema->mutex);
337 CHECK_STATUS("pthread_mutex_unlock");
287 dprintf(("down_sema(%lx) return\n", (long) sema)); 338 dprintf(("down_sema(%lx) return\n", (long) sema));
288 return -1; 339 return success;
289 } 340 }
290 341
291 void up_sema _P1(sema, type_sema sema) 342 void up_sema _P1(sema, type_sema sema)
292 { 343 {
344 int status, error = 0;
345 struct semaphore *thesema = (struct semaphore *) sema;
346
293 dprintf(("up_sema(%lx)\n", (long) sema)); 347 dprintf(("up_sema(%lx)\n", (long) sema));
294 } 348 status = pthread_mutex_lock(&thesema->mutex);
349 CHECK_STATUS("pthread_mutex_lock");
350 thesema->value++;
351 status = pthread_cond_signal(&thesema->cond);
352 CHECK_STATUS("pthread_cond_signal");
353 status = pthread_mutex_unlock(&thesema->mutex);
354 CHECK_STATUS("pthread_mutex_unlock");
355 }