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+PR_OpenSemaphore
+================
+
+Creates or opens a named semaphore with the specified name.
+
+
+Syntax
+------
+
+.. code::
+
+   #include <pripcsem.h>
+
+   #define PR_SEM_CREATE 0x1 /* create if not exist */
+
+   #define PR_SEM_EXCL 0x2 /* fail if already exists */
+
+   NSPR_API(PRSem *) PR_OpenSemaphore(
+     const char *name,
+     PRIntn flags,
+     PRIntn mode,
+     PRUintn value
+   );
+
+
+Parameters
+~~~~~~~~~~
+
+The function has the following parameters:
+
+``name``
+   The name to be given the semaphore.
+``flags``
+   How to create or open the semaphore.
+``mode``
+   Unix style file mode to be used when creating the semaphore.
+``value``
+   The initial value assigned to the semaphore.
+
+
+Returns
+~~~~~~~
+
+A pointer to a PRSem structure or ``NULL/code> on error.``
+
+
+Description
+~~~~~~~~~~~
+
+If the named semaphore doesn't exist and the ``PR_SEM_CREATE`` flag is
+specified, the named semaphore is created. The created semaphore needs
+to be removed from the system with a :ref:`PR_DeleteSemaphore` call.
+
+If ``PR_SEM_CREATE`` is specified, the third argument is the access
+permission bits of the new semaphore (same interpretation as the mode
+argument to :ref:`PR_Open`) and the fourth argument is the initial value of
+the new semaphore. ``If PR_SEM_CREATE`` is not specified, the third and
+fourth arguments are ignored.