panne 2002/06/30 13:59:59 PDT
Modified files:
libraries/GLUT Makefile
libraries/GLUT/Graphics/UI/GLUT/Callbacks Global.hs Window.hs
Added files:
libraries/GLUT/Graphics/UI/GLUT/Callbacks Registration.hs
Log:
After it was concluded on the FFI mailing list that freeing a FunPtr during the
callback itself is not a good idea, we bite the bullet and do it the hard (and
cunning :-) way:
* Because GLUT has no way to query callbacks, the FunPtrs to them are tracked
in global(!) table, using the standard unsafePerformIO-newIORef-trick.
* When an already existing callback is re-/unregistered, the old FunPtr to it
is put onto a cleanup list, which is again held in a global variable.
* When the cleanup list becomes non-empty, a scavenger is registered as an
immediate timer callback, which frees all FunPtrs on the cleanup list. The
FunPtr to the scavenger is held in a global (write-once) variable, but this
probably comes to no surprise... :-}
This all works without any synchronisation because GLUT is single-threaded, so
all callbacks are done sequentially.
Revision Changes Path
1.9 +7 -5 fptools/libraries/GLUT/Makefile
1.2 +9 -18 fptools/libraries/GLUT/Graphics/UI/GLUT/Callbacks/Global.hs
1.3 +3 -13 fptools/libraries/GLUT/Graphics/UI/GLUT/Callbacks/Window.hs
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