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Working semaphore implementation by Sjoerd.

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This commit is contained in:
Guido van Rossum 1997-01-17 21:06:41 +00:00
parent dd5db43905
commit 7af8130857
1 changed files with 64 additions and 3 deletions
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67
Python/thread_pthread.h
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@ -263,32 +263,93 @@ void release_lock _P1(lock, type_lock lock)
/* /*
* Semaphore support. * Semaphore support.
*/ */
/* NOTE: 100% non-functional at this time - tim */
struct semaphore {
pthread_mutex_t mutex;
pthread_cond_t cond;
int value;
};
type_sema allocate_sema _P1(value, int value) type_sema allocate_sema _P1(value, int value)
{ {
char *sema = 0; struct semaphore *sema;
int status, error = 0;
dprintf(("allocate_sema called\n")); dprintf(("allocate_sema called\n"));
if (!initialized) if (!initialized)
init_thread(); init_thread();
sema = (struct semaphore *) malloc(sizeof(struct semaphore));
if (sema != NULL) {
sema->value = value;
status = pthread_mutex_init(&sema->mutex,
pthread_mutexattr_default);
CHECK_STATUS("pthread_mutex_init");
status = pthread_cond_init(&sema->cond,
pthread_condattr_default);
CHECK_STATUS("pthread_cond_init");
if (error) {
free((void *) sema);
sema = NULL;
}
}
dprintf(("allocate_sema() -> %lx\n", (long) sema)); dprintf(("allocate_sema() -> %lx\n", (long) sema));
return (type_sema) sema; return (type_sema) sema;
} }
void free_sema _P1(sema, type_sema sema) void free_sema _P1(sema, type_sema sema)
{ {
int status, error = 0;
struct semaphore *thesema = (struct semaphore *) sema;
dprintf(("free_sema(%lx) called\n", (long) sema)); dprintf(("free_sema(%lx) called\n", (long) sema));
status = pthread_cond_destroy(&thesema->cond);
CHECK_STATUS("pthread_cond_destroy");
status = pthread_mutex_destroy(&thesema->mutex);
CHECK_STATUS("pthread_mutex_destroy");
free((void *) thesema);
} }
int down_sema _P2(sema, type_sema sema, waitflag, int waitflag) int down_sema _P2(sema, type_sema sema, waitflag, int waitflag)
{ {
int status, error = 0, success;
struct semaphore *thesema = (struct semaphore *) sema;
dprintf(("down_sema(%lx, %d) called\n", (long) sema, waitflag)); dprintf(("down_sema(%lx, %d) called\n", (long) sema, waitflag));
status = pthread_mutex_lock(&thesema->mutex);
CHECK_STATUS("pthread_mutex_lock");
if (waitflag) {
while (!error && thesema->value <= 0) {
status = pthread_cond_wait(&thesema->cond,
&thesema->mutex);
CHECK_STATUS("pthread_cond_wait");
}
}
if (error)
success = 0;
else if (thesema->value > 0) {
thesema->value--;
success = 1;
}
else
success = 0;
status = pthread_mutex_unlock(&thesema->mutex);
CHECK_STATUS("pthread_mutex_unlock");
dprintf(("down_sema(%lx) return\n", (long) sema)); dprintf(("down_sema(%lx) return\n", (long) sema));
return -1; return success;
} }
void up_sema _P1(sema, type_sema sema) void up_sema _P1(sema, type_sema sema)
{ {
int status, error = 0;
struct semaphore *thesema = (struct semaphore *) sema;
dprintf(("up_sema(%lx)\n", (long) sema)); dprintf(("up_sema(%lx)\n", (long) sema));
status = pthread_mutex_lock(&thesema->mutex);
CHECK_STATUS("pthread_mutex_lock");
thesema->value++;
status = pthread_cond_signal(&thesema->cond);
CHECK_STATUS("pthread_cond_signal");
status = pthread_mutex_unlock(&thesema->mutex);
CHECK_STATUS("pthread_mutex_unlock");
} }