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+PRCallOnceType
+==============
+
+Structure for tracking initialization.
+
+
+Syntax
+------
+
+.. code::
+
+   #include <prinit.h>
+
+   typedef struct PRCallOnceType {
+     PRIntn initialized;
+     PRInt32 inProgress;
+     PRStatus status;
+   } PRCallOnceType;
+
+
+Fields
+~~~~~~
+
+The structure has these fields:
+
+``initialized``
+   If not zero, the initialization process has been completed.
+``inProgress``
+   If not zero, the initialization process is currently being executed.
+   Calling threads that observe this status block until inProgress is
+   zero.
+``status``
+   An indication of the outcome of the initialization process.
+
+
+Description
+-----------
+
+The client is responsible for initializing the :ref:`PRCallOnceType`
+structure to all zeros. This initialization must be accomplished before
+any threading issues exist.