assert fail before allowing invalid thread id into use

src/libCom/osi/os/WIN32/osdThread.c

@@ -504,6 +504,7 @@ epicsShareFunc void epicsShareAPI epicsThreadSleep ( double seconds )
 epicsShareFunc epicsThreadId epicsShareAPI epicsThreadGetIdSelf (void) 
 {
     win32ThreadParam *pParm = (win32ThreadParam *) TlsGetValue (tlsIndexWIN32);
+    assert ( pParm ); /* very dangerous to allow non-unique thread id into use */
     return (epicsThreadId) pParm;
 }
 

src/libCom/osi/os/posix/osdThread.c

@@ -445,6 +445,7 @@ void epicsThreadSleep(double seconds)
 
 epicsThreadId epicsThreadGetIdSelf(void) {
     epicsThreadOSD *pthreadInfo = (epicsThreadOSD *)pthread_getspecific(getpthreadInfo);
+    assert ( pthreadInfo ); /* very dangerous to allow non-unique thread id into use */
     return(pthreadInfo);
 }