added a feature which brings up a error message box, if there was any issue with the msr-file when starting musrview from musredit.

src/include/PMsrHandler.h

@@ -32,6 +32,8 @@
 
 #include <string>
 #include <memory>
+#include <sstream>
+#include <string>
 
 #include <TString.h>
 #include <TComplex.h>
@@ -103,6 +105,8 @@ class PMsrHandler
 
     virtual void GetGroupingString(Int_t runNo, TString detector, TString &groupingStr);
     virtual Bool_t EstimateN0();
+    
+    virtual std::string GetLastErrorMsg() { return fLastErrorMsg.str(); }
 
     virtual std::string GetDKSTheoryString();
     virtual UInt_t GetDKSTag();
@@ -135,6 +139,8 @@ class PMsrHandler
 
     Int_t fNoOfMaps;
 
+    std::stringstream fLastErrorMsg;
+
     virtual Bool_t HandleFitParameterEntry(PMsrLines &line);
     virtual Bool_t HandleTheoryEntry(PMsrLines &line);
     virtual Bool_t HandleFunctionsEntry(PMsrLines &line);