Even Unix signals are delivered as Mach exceptions first. If the process doesn't have a Mach exception handler set up, the kernel's exception handler converts t

Even Unix signals are delivered as Mach exceptions first. If the process doesn't have a Mach exception handler set up, the kernel's exception handler converts them to Unix signals and tries delivery that way: https://github.com/opensource-apple/xnu/blob/27ffc00f33925b582391b1ef318b78b8bd3939d1/bsd/uxkern/ux_exception.c#L428 https://github.com/opensource-apple/xnu/blob/27ffc00f33925b5... and https://github.com/opensource-apple/xnu/blob/27ffc00f33925b582391b1ef318b78b8bd3939d1/bsd/dev/i386/unix_signal.c#L775 https://github.com/opensource-apple/xnu/blob/27ffc00f33925b5...