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[svn-r2348] The way the pthread_t object was being initialized wasn't correct for all

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platforms. Also, it's not entirely certain that a value of 0 isn't a
valid thread ID. So, I changed the pthread_t object to be a pointer to
pthread_t with the appropriate memory management this entails. Part of
the validity of this approach rests on the fact that one can assign a
variable which is a structure to another variable of the same type and
all fields within will be copied appropriately...See! C *does* do some
things correctly :-).
This commit is contained in:
Bill Wendling 2000-06-06 15:50:18 -05:00
parent 8cb2d8c6af
commit 90bc20edb5
2 changed files with 26 additions and 13 deletions
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37
src/H5TS.c
View File

@ -37,9 +37,6 @@ pthread_key_t H5TS_errstk_key_g;
pthread_key_t H5TS_cancel_key_g;
hbool_t H5TS_allow_concurrent_g = FALSE; /* concurrent APIs override this */
/* Local variable declarations */
static pthread_t H5TS_null_g; /* Set to ``null'' with HDmemset for comparing*/
/* Local function definitions */
#ifdef NOT_USED
static void H5TS_mutex_init(H5TS_mutex_t *mutex);
@ -72,8 +69,7 @@ H5TS_first_thread_init(void)
H5_g.H5_libinit_g = FALSE;
/* set the two pthread_t objects to ``null'' */
HDmemset(&H5_g.init_lock.owner_thread, 0, sizeof(pthread_t));
HDmemset(&H5TS_null_g, 0, sizeof(pthread_t));
H5_g.init_lock.owner_thread = NULL;
/* initialize global API mutex lock */
pthread_mutex_init(&H5_g.init_lock.atomic_lock, NULL);
@ -115,7 +111,7 @@ H5TS_first_thread_init(void)
static void
H5TS_mutex_init(H5TS_mutex_t *mutex)
{
HDmemset(&H5_g.init_lock.owner_thread, 0, sizeof(pthread_t));
H5_g.init_lock.owner_thread = NULL;
pthread_mutex_init(&mutex->atomic_lock, NULL);
pthread_cond_init(&mutex->cond_var, NULL);
mutex->lock_count = 0;
@ -157,20 +153,36 @@ H5TS_mutex_lock(H5TS_mutex_t *mutex)
if (ret_value)
return ret_value;
if (pthread_equal(pthread_self(), mutex->owner_thread)) {
if (mutex->owner_thread && pthread_equal(pthread_self(), *mutex->owner_thread)) {
/* already owned by self - increment count */
mutex->lock_count++;
} else if (pthread_equal(mutex->owner_thread, H5TS_null_g)) {
} else if (!mutex->owner_thread) {
/* no one else has locked it - set owner and grab lock */
mutex->owner_thread = pthread_self();
mutex->owner_thread = H5MM_malloc(sizeof(pthread_t));
if (!mutex->owner_thread) {
H5E_push(H5E_RESOURCE, H5E_NOSPACE, "H5TS_mutex_lock",
__FILE__, __LINE__, "memory allocation failed");
return FAIL;
}
*mutex->owner_thread = pthread_self();
mutex->lock_count = 1;
} else {
/* if already locked by someone else */
for (;;) {
pthread_cond_wait(&mutex->cond_var, &mutex->atomic_lock);
if (pthread_equal(mutex->owner_thread, H5TS_null_g)) {
mutex->owner_thread = pthread_self();
if (!mutex->owner_thread) {
mutex->owner_thread = H5MM_malloc(sizeof(pthread_t));
if (!mutex->owner_thread) {
H5E_push(H5E_RESOURCE, H5E_NOSPACE, "H5TS_mutex_lock",
__FILE__, __LINE__, "memory allocation failed");
return FAIL;
}
*mutex->owner_thread = pthread_self();
mutex->lock_count = 1;
break;
}
@ -219,7 +231,8 @@ H5TS_mutex_unlock(H5TS_mutex_t *mutex)
mutex->lock_count--;
if (mutex->lock_count == 0) {
HDmemset(&mutex->owner_thread, 0, sizeof(pthread_t));
H5MM_xfree(mutex->owner_thread);
mutex->owner_thread = NULL;
ret_value = pthread_cond_signal(&mutex->cond_var);
if (ret_value) {

2
src/H5TSprivate.h
View File

@ -25,7 +25,7 @@
/* Library level data structures */
typedef struct H5TS_mutex_struct {
pthread_t owner_thread; /* current lock owner */
pthread_t *owner_thread; /* current lock owner */
pthread_mutex_t atomic_lock; /* lock for atomicity of new mechanism */
pthread_cond_t cond_var; /* condition variable */
unsigned int lock_count;