Question

Is there a way to halt execution, somewhat like SIG_ABRT, but immediately, even if we’re not on the main thread?

Answer 1

Core Foundation has a macro HALT that should do the trick, if you really, really think it’s necessary to do this:

#if defined(__ppc__)
    #define HALT do {asm __volatile__("trap"); kill(getpid(), 9); } while (0)
#elif defined(__i386__) || defined(__x86_64__)
    #if defined(__GNUC__)
        #define HALT do {asm __volatile__("int3"); kill(getpid(), 9); } while (0)
    #elif defined(_MSC_VER)
        #define HALT do { DebugBreak(); abort(); } while (0)
    #else
        #error Compiler not supported
    #endif
#endif
#if defined(__arm__)
    #define HALT do {asm __volatile__("bkpt 0xCF"); kill(getpid(), 9); } while (0)
#endif