slightly improve error message

Author: berthubert

ubxtool.cc

@@ -411,8 +411,10 @@ int initFD(const char* fname, bool doRTSCTS)
   int fd;
   if (doDEBUG) { cerr<<humanTimeNow()<<" initFD()"<<endl; }
   if (!isPresent(fname)) {
+
     if (doDEBUG) { cerr<<humanTimeNow()<<" initFD - "<<fname<<" - not present"<<endl; }
-    throw runtime_error("Opening file "+string(fname));
+    
+    throw runtime_error("Opening file "+string(fname)+": not present)";
   }
   if(string(fname) != "stdin" && string(fname) != "/dev/stdin" && isCharDevice(fname)) {
     if (doDEBUG) { cerr<<humanTimeNow()<<" initFD - open("<<fname<<")"<<endl; }