About trapping integer division-by-zero errors with __rt_raise()

By default, integer division by zero returns zero. If you want to intercept division by zero, you can re-implement the C library helper function __rt_raise(). The function prototype for __rt_raise() is:

void __rt_raise(int signal, int type);

If you re-implement __rt_raise(), then the library will automatically provide the signal-handling library version of __aeabi_idiv0(), which calls __rt_raise(), then that library version of __aeabi_idiv0() is included in the final image.

In that case, when a divide-by-zero error occurs, __aeabi_idiv0() calls __rt_raise(SIGFPE, DIVBYZERO). Therefore, if you re-implement __rt_raise(), you must check (signal == SIGFPE) && (type == DIVBYZERO) to determine if division by zero has occurred.