lundi, février 29, 2016

Catch that!

Not so long ago, I was regretting that HandMade Hero was just giving debugging hints for weeks instead of talking of game engine and game design ... And I haven't posted myself anything about developing games but fixing and debugging since then. Hear this, fellow game developer. At some point, either you'll dig deep into debugging or you'll have to trash your project and move to another project, possibly from scratch.

Désolé pour ceux qui aiment les articles sur le dévelopement de jeu proprement dit. À ce stade-ci, soit je m'accroche et je continue à nettoyer le code malgré les difficultés techniques, soit je laisse tomber l'idée d'avoir un School Rush fiable. La bonne nouvelle c'est que peu à peu, les choses mystérieuses perdent de leur mystère et je progresse vers quelque-chose de mieux compris et mieux contrôlé.

Par exemple, si on lance une exception depuis un destructeur appelé lui-même suite au déclenchement d'une autre exception, la bibliothèque libstdc++ jette le gant et met fin au programme sans autre forme de procès.

Allez, soyez encore un peu patients. Je suis certains que vous trouverez que ça vaudra la peine d'avoir le niveau suivant chargé en moins de 2 secondes plutôt que d'attendre 20 secondes ou plus entre chaque essai.

how could we have terminate called ? 
Something was driving me nuts in those debugging/testing attempts: I couldn't get any exception properly reported, but instead the program terminated with the exception reaching top-level.
Of course, I asked for help on Stack Overflow, but the question got closed as noone could reproduce anything.


So here is how C++ could easily fail to catch your exception, and you know it happens when you see "terminate called recursively".  Don't let that "terminate called after throwing an instance of std::runtime_error (or whatever exception you've thrown) fool you. During stack unwinding, all destructors are invoked. If any of these try to throw an exception while unwinding the stack, we'll find ourselves into a recursive-terminate condition.


Oh, maybe you have the right to throw an exception and catch it before it leaves the stack frame of the destructor, but if the destructor-originated exception escape the exception-originated destructor call, then the exception management runtime apparently gives up and terminate the program.

Aucun commentaire: