[svn-r2286] Gave the threading functions return types (herr_t). pthreads' calls

return 0 on success and non-zero on failure. That's what happens with
these calls.

There was a problem compiling threading on Linux. The pthread_t type is
not consistent among different implementations, so it cannot simply be
assigned to NULL or tested against it. I initialize it by calling
HDmemset(foo_thread, 0, sizeof(pthread_t)). To see if it's a "null"
pthread, I created a special pthread_t object (assigned to only in the
init phase and then only read...i.e., thread safe) and assigned it "null"
as above. Then I use pthread_equal() to determine if the thread is null.

2 files changed, 163 insertions, 94 deletions

diff --git a/src/H5TS.c b/src/H5TS.c
index 37b7244..7c29a95 100644
--- a/src/H5TS.c
+++ b/src/H5TS.c
@@ -1,14 +1,14 @@
 /****************************************************************************
-* NCSA HDF                                                                 *
-* Software Development Group                                               *
-* National Center for Supercomputing Applications                          *
-* University of Illinois at Urbana-Champaign                               *
-* 605 E. Springfield, Champaign IL 61820                                   *
-*                                                                          *
-* For conditions of distribution and use, see the accompanying             *
-* hdf/COPYING file.                                                        *
-*                                                                          *
-****************************************************************************/
+ * NCSA HDF                                                                 *
+ * Software Development Group                                               *
+ * National Center for Supercomputing Applications                          *
+ * University of Illinois at Urbana-Champaign                               *
+ * 605 E. Springfield, Champaign IL 61820                                   *
+ *                                                                          *
+ * For conditions of distribution and use, see the accompanying             *
+ * hdf/COPYING file.                                                        *
+ *                                                                          *
+ ****************************************************************************/
 
 #ifdef RCSID
 static char             RcsId[] = "@(#)$Revision$";
@@ -17,8 +17,9 @@ static char             RcsId[] = "@(#)$Revision$";
 /* $Id$ */
 
 /* private headers */
-#include <H5private.h>          /*library                 		*/
-#include <H5Eprivate.h>         /*error handling          		*/
+#include <H5private.h>		/*library                 		*/
+#include <H5Eprivate.h>		/*error handling          		*/
+#include <H5MMprivate.h>	/*memory management functions		*/
 
 #ifdef H5_HAVE_THREADSAFE
 
@@ -26,8 +27,8 @@ static char             RcsId[] = "@(#)$Revision$";
 
 /* cancelability structure */
 typedef struct H5TS_cancel_struct {
-  int previous_state;
-  unsigned int cancel_count;
+    int previous_state;
+    unsigned int cancel_count;
 } H5TS_cancel_t;
 
 /* Global variable definitions */
@@ -36,6 +37,9 @@ 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);
@@ -44,15 +48,16 @@ static void H5TS_mutex_init(H5TS_mutex_t *mutex);
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_first_thread_init
+ *
  * USAGE
  *    H5TS_first_thread_init()
  * 
  * RETURNS
  *
  * DESCRIPTION
- *   Initialization of global API lock, keys for per-thread error stacks
- *   and cancallability information. Called by the first thread that enters
- *   the library.
+ *   Initialization of global API lock, keys for per-thread error stacks and
+ *   cancallability information. Called by the first thread that enters the
+ *   library.
  *
  * PROGRAMMER: Chee Wai LEE
  *             May 2, 2000
@@ -64,17 +69,21 @@ static void H5TS_mutex_init(H5TS_mutex_t *mutex);
 void
 H5TS_first_thread_init(void)
 {
-    /* initialize global API mutex lock                      */
     H5_g.H5_libinit_g = FALSE;
-    H5_g.init_lock.owner_thread = NULL;
+
+    /* 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));
+
+    /* initialize global API mutex lock */
     pthread_mutex_init(&H5_g.init_lock.atomic_lock, NULL);
     pthread_cond_init(&H5_g.init_lock.cond_var, NULL);
     H5_g.init_lock.lock_count = 0;
 
-    /* initialize key for thread-specific error stacks       */
+    /* initialize key for thread-specific error stacks */
     pthread_key_create(&H5TS_errstk_key_g, NULL);
 
-    /* initialize key for thread cancellability mechanism    */
+    /* initialize key for thread cancellability mechanism */
     pthread_key_create(&H5TS_cancel_key_g, NULL);
 }
 
@@ -82,119 +91,155 @@ H5TS_first_thread_init(void)
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_mutex_init
+ *
  * USAGE
  *    H5TS_mutex_init(&mutex_var)
  * 
  * RETURNS
  *
  * DESCRIPTION
- *  Recursive lock semantics for HDF5 (lock initialization) -
- *  Multiple acquisition of a lock by a thread is permitted with a
- *  corresponding unlock operation required.
+ *    Recursive lock semantics for HDF5 (lock initialization) -
+ *    Multiple acquisition of a lock by a thread is permitted with a
+ *    corresponding unlock operation required.
  *
  * PROGRAMMER: Chee Wai LEE
  *             May 2, 2000
  *
  * MODIFICATIONS:
  *
+ *    19 May 2000, Bill Wendling
+ *    Changed (*foo). form of accessing structure members to the -> form.
+ *
  *--------------------------------------------------------------------------
  */
 static void
 H5TS_mutex_init(H5TS_mutex_t *mutex)
 {
-    (*mutex).owner_thread = NULL;
-    pthread_mutex_init(&(*mutex).atomic_lock, NULL);
-    pthread_cond_init(&(*mutex).cond_var, NULL);
-    (*mutex).lock_count = 0;
+    HDmemset(&H5_g.init_lock.owner_thread, 0, sizeof(pthread_t));
+    pthread_mutex_init(&mutex->atomic_lock, NULL);
+    pthread_cond_init(&mutex->cond_var, NULL);
+    mutex->lock_count = 0;
 }
 #endif /* NOT_USED */
 
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_mutex_lock
+ *
  * USAGE
  *    H5TS_mutex_lock(&mutex_var)
  * 
  * RETURNS
+ *    0 on success and non-zero on error.
  *
  * DESCRIPTION
- *  Recursive lock semantics for HDF5 (locking) -
- *  Multiple acquisition of a lock by a thread is permitted with a
- *  corresponding unlock operation required.
+ *    Recursive lock semantics for HDF5 (locking) -
+ *    Multiple acquisition of a lock by a thread is permitted with a
+ *    corresponding unlock operation required.
  *
  * PROGRAMMER: Chee Wai LEE
  *             May 2, 2000
  *
  * MODIFICATIONS:
  *
+ *    19 May 2000, Bill Wendling
+ *    Changed (*foo). form of accessing structure members to the -> form.
+ *
  *--------------------------------------------------------------------------
  */
-void
+herr_t
 H5TS_mutex_lock(H5TS_mutex_t *mutex)
 {
-    pthread_mutex_lock(&(*mutex).atomic_lock);
-    if (pthread_equal(pthread_self(), (*mutex).owner_thread)) {
+    herr_t ret_value;
+
+    ret_value = pthread_mutex_lock(&mutex->atomic_lock);
+
+    if (ret_value)
+	    return ret_value;
+
+    if (pthread_equal(pthread_self(), mutex->owner_thread)) {
         /* already owned by self - increment count */
-        (*mutex).lock_count++;
+        mutex->lock_count++;
+    } else if (pthread_equal(mutex->owner_thread, H5TS_null_g)) {
+        /* no one else has locked it - set owner and grab lock */
+        mutex->owner_thread = pthread_self();
+        mutex->lock_count = 1;
     } else {
-        if ((*mutex).owner_thread == NULL) {
-            /* no one else has locked it - set owner and grab lock */
-            (*mutex).owner_thread = pthread_self();
-            (*mutex).lock_count = 1;
-        } else {
-            /* if already locked by someone else */
-            while (1) {
-                pthread_cond_wait(&(*mutex).cond_var, &(*mutex).atomic_lock);
-                if ((*mutex).owner_thread == NULL) {
-                    (*mutex).owner_thread = pthread_self();
-                    (*mutex).lock_count = 1;
-                    break;
-                } /* else do nothing and loop back to wait on condition*/
-            }
+        /* 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();
+	        mutex->lock_count = 1;
+	        break;
+	    }
         }
     }
-    pthread_mutex_unlock(&(*mutex).atomic_lock);
+
+    return pthread_mutex_unlock(&mutex->atomic_lock);
 }
 
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_mutex_unlock
+ *
  * USAGE
  *    H5TS_mutex_unlock(&mutex_var)
  * 
  * RETURNS
+ *    0 on success and non-zero on error.
  *
  * DESCRIPTION
- *  Recursive lock semantics for HDF5 (unlocking) -
- *  Multiple acquisition of a lock by a thread is permitted with a
- *  corresponding unlock operation required.
+ *    Recursive lock semantics for HDF5 (unlocking) -
+ *    Multiple acquisition of a lock by a thread is permitted with a
+ *    corresponding unlock operation required.
  *
  * PROGRAMMER: Chee Wai LEE
  *             May 2, 2000
  *
  * MODIFICATIONS:
  *
+ *    19 May 2000, Bill Wendling
+ *    Changed (*foo). form of accessing structure members to the -> form.
+ *    Also gave the function a return value.
+ *
  *--------------------------------------------------------------------------
  */
-void
+herr_t
 H5TS_mutex_unlock(H5TS_mutex_t *mutex)
 {
-    pthread_mutex_lock(&(*mutex).atomic_lock);
-    (*mutex).lock_count--;
-    if ((*mutex).lock_count == 0) {
-        (*mutex).owner_thread = NULL;
-        pthread_cond_signal(&(*mutex).cond_var);
+    herr_t ret_value;
+
+    ret_value = pthread_mutex_lock(&mutex->atomic_lock);
+
+    if (ret_value)
+	    return ret_value;
+
+    mutex->lock_count--;
+
+    if (mutex->lock_count == 0) {
+	HDmemset(&mutex->owner_thread, 0, sizeof(pthread_t));
+        ret_value = pthread_cond_signal(&mutex->cond_var);
+
+	if (ret_value) {
+	    pthread_mutex_unlock(&mutex->atomic_lock);
+	    return ret_value;
+	}
     }
-    pthread_mutex_unlock(&(*mutex).atomic_lock);
+
+    return pthread_mutex_unlock(&mutex->atomic_lock);
 }
 
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_cancel_count_inc
+ *
  * USAGE
  *    H5TS_cancel_count_inc()
  * 
  * RETURNS
+ *    0 on success non-zero error code on error.
  *
  * DESCRIPTION
  *    Creates a cancelation counter for a thread if it is the first time
@@ -210,41 +255,59 @@ H5TS_mutex_unlock(H5TS_mutex_t *mutex)
  *
  * MODIFICATIONS:
  *
+ *    19 May 2000, Bill Wendling
+ *    Changed function to return a value. Also changed the malloc() call to
+ *    the H5MM_malloc() call and checked the returned pointer.
+ *
  *--------------------------------------------------------------------------
  */
-void
+herr_t
 H5TS_cancel_count_inc(void)
 {
     H5TS_cancel_t *cancel_counter;
+    herr_t ret_value = 0;
 
-    if ((cancel_counter = pthread_getspecific(H5TS_cancel_key_g))!=NULL) {
-        /* do nothing here */
-    } else {
-        /* first time thread calls library - create new counter and associate
-         *  with key
+    cancel_counter = pthread_getspecific(H5TS_cancel_key_g);
+
+    if (!cancel_counter) {
+        /*
+	 * First time thread calls library - create new counter and associate
+         * with key
          */
-        cancel_counter = (H5TS_cancel_t *)malloc(sizeof(H5TS_cancel_t));
+	cancel_counter = H5MM_malloc(sizeof(H5TS_cancel_t));
+
+	if (!cancel_counter) {
+	    H5E_push(H5E_RESOURCE, H5E_NOSPACE, "H5TS_cancel_count_inc",
+		     __FILE__, __LINE__, "memory allocation failed");
+	    return FAIL;
+	}
+
         cancel_counter->cancel_count = 0;
-        pthread_setspecific(H5TS_cancel_key_g, (void *)cancel_counter);
+        ret_value = pthread_setspecific(H5TS_cancel_key_g,
+					(void *)cancel_counter);
     }
 
-    if (cancel_counter->cancel_count == 0) {
+    if (cancel_counter->cancel_count == 0)
         /* thread entering library */
-        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &(cancel_counter->previous_state));
-    }
-    cancel_counter->cancel_count++;
+        ret_value = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE,
+					   &cancel_counter->previous_state);
+
+    ++cancel_counter->cancel_count;
+    return ret_value;
 }
 
 /*--------------------------------------------------------------------------
  * NAME
  *    H5TS_cancel_count_dec
+ *
  * USAGE
  *    H5TS_cancel_count_dec()
  *   
  * RETURNS
+ *    0 on success and a non-zero error code on error.
  *
  * DESCRIPTION
- *    if counter value is one, then set cancelability type of the thread
+ *    If counter value is one, then set cancelability type of the thread
  *    to the previous cancelability type stored in the cancelation counter.
  *    (the thread is leaving the library).
  *
@@ -255,17 +318,24 @@ H5TS_cancel_count_inc(void)
  *
  * MODIFICATIONS:
  *
+ *    19 May 2000, Bill Wendling
+ *    Changed so that function returns a value. May be of limited usefulness.
+ *
  *--------------------------------------------------------------------------
  */
-void
+herr_t
 H5TS_cancel_count_dec(void)
 {
-    H5TS_cancel_t *cancel_counter = pthread_getspecific(H5TS_cancel_key_g);
+    herr_t ret_value = 0;
+    register H5TS_cancel_t *cancel_counter;
 
-    if (cancel_counter->cancel_count == 1) {
-        pthread_setcancelstate(cancel_counter->previous_state, NULL);
-    }
-    cancel_counter->cancel_count--;
+    cancel_counter = pthread_getspecific(H5TS_cancel_key_g);
+
+    if (cancel_counter->cancel_count == 1)
+        ret_value = pthread_setcancelstate(cancel_counter->previous_state, NULL);
+
+    --cancel_counter->cancel_count;
+    return ret_value;
 }
 
-#endif
+#endif	/* H5_HAVE_THREADSAFE */
diff --git a/src/H5TSprivate.h b/src/H5TSprivate.h
index 601b6f0..525450c 100644
--- a/src/H5TSprivate.h
+++ b/src/H5TSprivate.h
@@ -14,8 +14,8 @@
  *
  *-------------------------------------------------------------------------
  */
-#ifndef _H5TSprivate_H
-#define _H5TSprivate_H
+#ifndef H5TSprivate_H_
+#define H5TSprivate_H_
 
 /* Public headers needed by this file */
 #ifdef LATER
@@ -25,10 +25,10 @@
 /* Library level data structures */
 
 typedef struct H5TS_mutex_struct {
-  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;
+    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;
 } H5TS_mutex_t;
 
 /* Extern global variables */
@@ -38,17 +38,16 @@ extern pthread_key_t H5TS_errstk_key_g;
 #if defined c_plusplus || defined __cplusplus
 extern      "C"
 {
-#endif                          /* c_plusplus || __cplusplus */
+#endif	/* c_plusplus || __cplusplus */
 
 __DLL__ void H5TS_first_thread_init(void);
-__DLL__ void H5TS_mutex_lock(H5TS_mutex_t *mutex);
-__DLL__ void H5TS_mutex_unlock(H5TS_mutex_t *mutex);
-__DLL__ void H5TS_cancel_count_inc(void);
-__DLL__ void H5TS_cancel_count_dec(void);
+__DLL__ herr_t H5TS_mutex_lock(H5TS_mutex_t *mutex);
+__DLL__ herr_t H5TS_mutex_unlock(H5TS_mutex_t *mutex);
+__DLL__ herr_t H5TS_cancel_count_inc(void);
+__DLL__ herr_t H5TS_cancel_count_dec(void);
 
 #if defined c_plusplus || defined __cplusplus
 }
-#endif                          /* c_plusplus || __cplusplus */
-
-#endif  /* _H5TSprivate_H */
+#endif	/* c_plusplus || __cplusplus */
 
+#endif	/* H5TSprivate_H_ */