1 files changed, 120 insertions, 0 deletions
diff --git a/pthread_rwlock_trywrlock.c b/pthread_rwlock_trywrlock.c
new file mode 100644
index 0000000..48bae9f
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+++ b/pthread_rwlock_trywrlock.c
@@ -0,0 +1,120 @@
+/*
+ * pthread_rwlock_trywrlock.c
+ *
+ * Description:
+ * This translation unit implements read/write lock primitives.
+ *
+ * --------------------------------------------------------------------------
+ *
+ *      Pthreads-win32 - POSIX Threads Library for Win32
+ *      Copyright(C) 1998 John E. Bossom
+ *      Copyright(C) 1999,2002 Pthreads-win32 contributors
+ * 
+ *      Contact Email: rpj@ise.canberra.edu.au
+ * 
+ *      The current list of contributors is contained
+ *      in the file CONTRIBUTORS included with the source
+ *      code distribution. The list can also be seen at the
+ *      following World Wide Web location:
+ *      http://sources.redhat.com/pthreads-win32/contributors.html
+ * 
+ *      This library is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU Lesser General Public
+ *      License as published by the Free Software Foundation; either
+ *      version 2 of the License, or (at your option) any later version.
+ * 
+ *      This library is distributed in the hope that it will be useful,
+ *      but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *      Lesser General Public License for more details.
+ * 
+ *      You should have received a copy of the GNU Lesser General Public
+ *      License along with this library in the file COPYING.LIB;
+ *      if not, write to the Free Software Foundation, Inc.,
+ *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <errno.h>
+#include <limits.h>
+
+#include "pthread.h"
+#include "implement.h"
+
+int
+pthread_rwlock_trywrlock(pthread_rwlock_t * rwlock)
+{
+    int result, result1;
+    pthread_rwlock_t rwl;
+
+    if (rwlock == NULL || *rwlock == NULL)
+      {
+	return EINVAL;
+      }
+
+    /*
+     * We do a quick check to see if we need to do more work
+     * to initialise a static rwlock. We check
+     * again inside the guarded section of ptw32_rwlock_check_need_init()
+     * to avoid race conditions.
+     */
+    if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
+      {
+	result = ptw32_rwlock_check_need_init(rwlock);
+
+	if (result != 0 && result != EBUSY)
+	  {
+	    return result;
+	  }
+      }
+
+    rwl = *rwlock;
+
+    if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
+      {
+	return EINVAL;
+      }
+
+    if ((result = pthread_mutex_trylock(&(rwl->mtxExclusiveAccess))) != 0)
+      {
+	return result;
+      }
+
+    if ((result = pthread_mutex_trylock(&(rwl->mtxSharedAccessCompleted))) != 0)
+      {
+	result1 = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
+	return ((result1 != 0) ? result1 : result);
+      }
+
+    if (rwl->nExclusiveAccessCount == 0) 
+      {
+	if (rwl->nCompletedSharedAccessCount > 0) 
+	  {
+	    rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
+	    rwl->nCompletedSharedAccessCount = 0;
+	  }
+
+	if (rwl->nSharedAccessCount > 0) 
+	  {
+	    if ((result = pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted))) != 0)
+	      {
+		(void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess));
+		return result;
+	      }
+
+	    if ((result = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess))) == 0)
+	      {
+		result = EBUSY;
+	      }
+	  }
+	else
+	  {
+	    rwl->nExclusiveAccessCount = 1;
+	  }
+      }
+    else 
+      {
+	result = EBUSY;
+      }
+
+    return result;
+}