Use this function to trigger a breakpoint during debugging.
void SDL_TriggerBreakpoint(void)
If the program is running under a debugger this function will trigger a breakpoint. It is typically used temporarily during debugging or with other error handling. Note that if a debugger isn't running, on some platforms this can terminate your application.
This isn't actually a function, but rather a macro. The intention is that the debugger will stop on exactly this line of code instead of somewhere inside the SDL library. As such, the assertion facility uses this so that the debugger stops on the exact line of code where an SDL_assert failed.