Add support for detection and processing of clean program termination request.

The default handling of cmd-Q/Quit program under MacOS was to terminate the
program if all its windows are closed without returning from FLTK's event loop.
This was running against a strong design feature of FLTK that programs
should always complete their event loop and return from main() when cleanly
terminating.

In the new code for the MacOS platform, cmd-Q/Quit program no longer terminates
the program. Instead, the event loop is interrupted and a call to Fl::program_should_quit()
allows to detect that program termination has been requested, if necessary.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12647 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 4 insertions, 1 deletions

diff --git a/FL/Fl_System_Driver.H b/FL/Fl_System_Driver.H
index 5bcd8e994..a543906fd 100644
--- a/FL/Fl_System_Driver.H
+++ b/FL/Fl_System_Driver.H
@@ -4,7 +4,7 @@
 // A base class for platform specific system calls
 // for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2010-2017 by Bill Spitzak and others.
+// Copyright 2010-2018 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -225,6 +225,9 @@ public:
   virtual const char *meta_name() { return "Meta"; }
   virtual const char *alt_name() { return "Alt"; }
   virtual const char *control_name() { return "Ctrl"; }
+  // The default implementation of the next 2 functions may be enough.
+  virtual int run_also_windowless();
+  virtual int wait_also_windowless(double delay);
 };
 
 #endif // FL_SYSTEM_DRIVER_H