*/
private OExtVar compileExtVar(Variable src) {
if (!src.isExternal())
return null;
OExtVar oextvar = new OExtVar(_oprocess);
oextvar.externalVariableId = src.getExternalId();
oextvar.debugInfo = createDebugInfo(src, null);
if (src.getExternalId() == null)
throw new CompilationException(__cmsgs.errMustSpecifyExternalVariableId(src.getName()));