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diff --git a/pthread_once.c b/pthread_once.c
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+/*
+ * 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) 1999,2002 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 "pthread.h"
+#include "implement.h"
+
+
+int
+pthread_once (
+	       pthread_once_t * once_control,
+	       void (*init_routine) (void)
+)
+	/*
+	 * ------------------------------------------------------
+	 * DOCPUBLIC
+	 *	If any thread in a process  with  a  once_control  parameter
+	 *	makes  a  call to pthread_once(), the first call will summon
+	 *	the init_routine(), but  subsequent  calls  will  not. The
+	 *	once_control  parameter  determines  whether  the associated
+	 *	initialization routine has been called.  The  init_routine()
+	 *	is complete upon return of pthread_once().
+	 *	This function guarantees that one and only one thread
+	 *	executes the initialization routine, init_routine when
+	 *	access is controlled by the pthread_once_t control
+	 *	key.
+	 *
+	 * PARAMETERS
+	 *	once_control
+	 *		pointer to an instance of pthread_once_t
+	 *
+	 *	init_routine
+	 *		pointer to an initialization routine
+	 *
+	 *
+	 * DESCRIPTION
+	 *	See above.
+	 *
+	 * RESULTS
+	 *		0		success,
+	 *		EINVAL		once_control or init_routine is NULL
+	 *
+	 * ------------------------------------------------------
+	 */
+{
+  int result;
+
+  if (once_control == NULL || init_routine == NULL)
+    {
+
+      result = EINVAL;
+      goto FAIL0;
+
+    }
+  else
+    {
+      result = 0;
+    }
+
+  if (!once_control->done)
+    {
+      if (InterlockedIncrement (&(once_control->started)) == 0)
+	{
+	  /*
+	   * First thread to increment the started variable
+	   */
+	  (*init_routine) ();
+	  once_control->done = TRUE;
+
+	}
+      else
+	{
+	  /*
+	   * Block until other thread finishes executing the onceRoutine
+	   */
+	  while (!(once_control->done))
+	    {
+	      /*
+	       * The following gives up CPU cycles without pausing
+	       * unnecessarily
+	       */
+	      Sleep (0);
+	    }
+	}
+    }
+
+  /*
+   * Fall through Intentionally
+   */
+
+  /*
+   * ------------
+   * Failure Code
+   * ------------
+   */
+FAIL0:
+  return (result);
+
+}				/* pthread_once */