Make mutex exception classes derive from std::exception.

src/libCom/osi/epicsMutex.cpp

@@ -50,7 +50,34 @@ struct epicsMutexParm {
 };
 
 STATIC epicsMutexOSD * epicsMutexGlobalLock;
-
+
+
+// vxWorks 5.4 gcc fails during compile when I use std::exception
+using namespace std;
+
+// exception payload
+class epicsMutex::mutexCreateFailed : public exception
+{
+    const char * what () const throw ();
+};
+
+const char * epicsMutex::mutexCreateFailed::what () const throw ()
+{
+    return "epicsMutex::mutexCreateFailed()";
+}
+
+// exception payload
+class epicsMutex::invalidMutex : public exception
+{
+    const char * what () const throw ();
+};
+
+const char * epicsMutex::invalidMutex::what () const throw ()
+{
+    return "epicsMutex::invalidMutex()";
+}
+
+
 epicsMutexId epicsShareAPI epicsMutexOsiCreate(
     const char *pFileName,int lineno)
 {

src/libCom/osi/epicsMutex.h

@@ -25,8 +25,8 @@ typedef enum {
 
 class epicsShareClass epicsMutex {
 public:
-    class mutexCreateFailed {}; /* exception */
-    class invalidMutex {}; /* exception */
+    class mutexCreateFailed; /* exception payload */
+    class invalidMutex; /* exception payload */
     epicsMutex ();
     ~epicsMutex ();
     void show ( unsigned level ) const;