allow to cancel exiting if editor tabs are modified and exit is requested in gui * file-editor-interface.h: new function check_closing * file-editor-tab.cc (ctor): set default for app_closing to 0 (not closing); (check_file_modified): dialog boxes for modified editor tabs depending on app closing or not; (conditional_close): no slot, but ordinary function returning close result; * file-editor-tab.h: conditional_close is function, not a slot; _app_closing is now int for closing from gui, from octave, not closing * file-editor.cc (dtor): calling new function check_closing if there are open tabs (exit requested octave), do not save session here since the tabs might already have been closed; (check_closing): new function saving session info and closing all tabs, stop closing tabs and returning false if user cancels exiting if there is a modified tab; (request_close_file, request_close_all_files, request_close_other_files, handle_tab_close_request): use conditional_close instead of signal; (construct): do not connect old signal for closing the tabs * file-editor.h: remove signal fetab_close_request, new function check_closing * main-window.cc (confirm_exit_octave): call file_editor::check_closing before really closing the app

--- a/libgui/src/m-editor/file-editor.h
+++ b/libgui/src/m-editor/file-editor.h
@@ -69,7 +69,6 @@
 signals:
 
   void fetab_settings_changed (const QSettings *settings);
-  void fetab_close_request (const QWidget* ID, bool app_closing = false);
   void fetab_change_request (const QWidget* ID);
   void fetab_file_name_query (const QWidget* ID);
   // Save is a ping-pong type of communication
@@ -117,6 +116,7 @@
 
 public slots:
   void focus (void);
+  bool check_closing (int closing_state);
 
   void request_new_file (const QString& commands);
   void request_new_script (const QString& commands);