1 files changed, 86 insertions, 0 deletions
diff --git a/pthreads/pthread_once.c b/pthreads/pthread_once.c
new file mode 100644
index 000000000..96d45f297
--- /dev/null
+++ b/pthreads/pthread_once.c
@@ -0,0 +1,86 @@
+/*
+ * pthread_once.c
+ *
+ * Description:
+ * This translation unit implements miscellaneous thread functions.
+ *
+ * --------------------------------------------------------------------------
+ *
+ *      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 "pthread.h"
+#include "implement.h"
+
+
+static void PTW32_CDECL
+ptw32_once_on_init_cancel (void * arg)
+{
+  /* when the initting thread is cancelled we have to release the lock */
+  ptw32_mcs_local_node_t *node = (ptw32_mcs_local_node_t *)arg;
+  ptw32_mcs_lock_release(node);
+}
+
+int
+pthread_once (pthread_once_t * once_control, void (*init_routine) (void))
+{
+  if (once_control == NULL || init_routine == NULL)
+    {
+      return EINVAL;
+    }
+  
+  if (!InterlockedExchangeAdd((LPLONG)&once_control->done, 0)) /* MBR fence */
+    {
+      ptw32_mcs_local_node_t node;
+
+      ptw32_mcs_lock_acquire((ptw32_mcs_lock_t *)&once_control->lock, &node);
+
+      if (!once_control->done)
+	{
+
+#ifdef _MSC_VER
+#pragma inline_depth(0)
+#endif
+
+	  pthread_cleanup_push(ptw32_once_on_init_cancel, (void *)&node);
+	  (*init_routine)();
+	  pthread_cleanup_pop(0);
+
+#ifdef _MSC_VER
+#pragma inline_depth()
+#endif
+
+	  once_control->done = PTW32_TRUE;
+	}
+
+	ptw32_mcs_lock_release(&node);
+    }
+
+  return 0;
+
+}				/* pthread_once */