?

src/edif.cpp

@@ -821,6 +821,8 @@ void NEdif::ReadTab( bool multiblock, bool fromscript )
         }
         olf.VS.push_back(S);
     }
+    if( !(olf.nScan()) )
+        throw string( "no input lines" );
 
     NOlm::SelNew();
     NOlm::OloAdd(&olf);

src/opr.cpp

@@ -397,6 +397,8 @@ void NOperate::IntXY(void)
         fout.xco = xco;
         fout.yco = yco;
         S.Clear();
+        if( !(fin->nScan()) )
+            throw string( "input file has no scans" );
         S.z = fin->VS[0].z;
         S.z.pop_back();
         for (uint j=0; j<fin->nScan(); j++) {