Use abort() in SDL_AbortAssertion()

[slouken]

It would probably be better to use abort() on platforms that can usefully support it (at least Unix) so that the process exits abnormally - on Unix platforms, being killed by a fatal signal is distinguishable from exiting normally, and abort() is documented to make the process kill itself with SIGABRT, which will often leave a core dump.

abort() is guaranteed by C99, but on e.g. Windows I know that SDL tries to avoid mandatory libc dependencies, so probably it can't use abort() and an ordinary exit status is the best (or least-bad) thing to do here. Or I suppose perhaps it could intentionally crash by executing a trap instruction or something?

Originally posted by @smcv in #13943 (comment)

[icculus]

Alternatives to abort():

• On Clang and GCC, __builtin_trap() generates a ud2 instruction, which crashes the app with the windows equivalent of SIGILL (which the debugger can catch, and outside of a debugger, kills the process with an abnormal exit). clang: https://godbolt.org/z/38z5693r4 gcc: https://godbolt.org/z/PYrvcEoT9
• On MSVC: __debugbreak() generates an int $3: https://godbolt.org/z/aGsz1hnWr ... different exception, same idea.
• Both of these macros will do the right thing on whatever CPU arch is being targeted, and they don't need a C runtime.

[madebr]

So effectively something like the following?

#if defined(HAVE_LIBC)
# define SDL_abort() abort()
#else
# define SDL_abort() do { SDL_TriggerBreakpoint(); SDL_ExitProcess(42); } while (0)
#endif

[icculus]

Oh, yeah, probably exactly that. :)

[smcv]

Yes, anywhere that we're intentionally crashing with an assertion failure or fatal error, either abort() or SDL_TriggerBreakpoint() seems a fine way to do that, and either is more appropriate than the various variations of _Exit() used in SDL_ExitProcess().

[slouken]

So effectively something like the following?
...

@madebr, this sounds good. Do you want to make a PR for this?

[madebr]

So effectively something like the following?
...

@madebr, this sounds good. Do you want to make a PR for this?

Ok! In SDL_internal.h or as a public api?

[slouken]

This can be internal.