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, 16 insertions, 0 deletions

diff --git a/src/Fl.cxx b/src/Fl.cxx
index ca629ab94..e6af1297b 100644
--- a/src/Fl.cxx
+++ b/src/Fl.cxx
@@ -589,6 +589,22 @@ int Fl::ready()
   return screen_driver()->ready();
 }
 
+/** Run the event loop even without any mapped window if the platform supports it.
+ \return zero indicates the event loop has been terminated.
+ */
+int Fl::run_also_windowless() {
+  return Fl::system_driver()->run_also_windowless();
+}
+
+/** Wait for \p delay seconds or until an event occurs, even without any mapped window if the platform supports it.
+ \return non zero indicates the event loop should be terminated
+ */
+int Fl::wait_also_windowless(double delay) {
+  return Fl::system_driver()->wait_also_windowless(delay);
+}
+
+int Fl::program_should_quit_ = 0;
+
 ////////////////////////////////////////////////////////////////
 // Window list management: