1 files changed, 103 insertions, 0 deletions
diff --git a/pthreads/pthread_rwlock_tryrdlock.c b/pthreads/pthread_rwlock_tryrdlock.c
new file mode 100644
index 000000000..308900d14
--- /dev/null
+++ b/pthreads/pthread_rwlock_tryrdlock.c
@@ -0,0 +1,103 @@
+/*
+ * pthread_rwlock_tryrdlock.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) 1999,2005 Pthreads-win32 contributors
+ * 
+ *      Contact Email: rpj@callisto.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_tryrdlock (pthread_rwlock_t * rwlock)
+{
+  int result;
+  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 (++rwl->nSharedAccessCount == INT_MAX)
+    {
+      if ((result =
+	   pthread_mutex_lock (&(rwl->mtxSharedAccessCompleted))) != 0)
+	{
+	  (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
+	  return result;
+	}
+
+      rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
+      rwl->nCompletedSharedAccessCount = 0;
+
+      if ((result =
+	   pthread_mutex_unlock (&(rwl->mtxSharedAccessCompleted))) != 0)
+	{
+	  (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
+	  return result;
+	}
+    }
+
+  return (pthread_mutex_unlock (&rwl->mtxExclusiveAccess));
+}