Added pj_thread_is_registered

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@674 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjlib/include/pj/os.h b/pjlib/include/pj/os.h
index ad2b49b..2720e7f 100644
--- a/pjlib/include/pj/os.h
+++ b/pjlib/include/pj/os.h
@@ -130,6 +130,14 @@
 					  pj_thread_t **thread);
 
 /**
+ * Check if this thread has been registered to PJLIB.
+ *
+ * @return		Non-zero if it is registered.
+ */
+PJ_DECL(pj_status_t) pj_thread_is_registered(void);
+
+
+/**
  * Get thread name.
  *
  * @param thread    The thread handle.