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/PMsgBox.h

@@ -0,0 +1,54 @@
+/***************************************************************************
+
+  PMsgBox.h
+
+  Author: Andreas Suter
+  e-mail: andreas.suter@psi.ch
+
+***************************************************************************/
+
+/***************************************************************************
+ *   Copyright (C) 2007-2025 by Andreas Suter                              *
+ *   andreas.suter@psi.ch                                                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ ***************************************************************************/
+
+#ifndef _PMSGBOX_H_
+#define _PMSGBOX_H_
+
+#include <string>
+
+#include <TApplication.h>
+#include <TGClient.h>
+#include <TGButton.h>
+#include <TGListBox.h>
+#include <TList.h>
+
+class PMsgBox : public TGMainFrame {
+
+private:
+   TGListBox *fListBox;
+
+public:
+   PMsgBox(const std::string errMsg, const TGWindow *p, UInt_t w, UInt_t h);
+   ~PMsgBox() override;
+   void DoExit();
+
+   ClassDefOverride(PMsgBox, 0)
+};
+
+#endif // _PMSGBOX_H_