[fweimer]

I'm pretty sure IEEE 754 covers trapping floating point math. It's not just about in-band signaling. It's unfortunate that the standard is proprietary, so we can't easily reference it to figure out what it says.

Anyway, most CPUs support a trapping mode, after all. Here's an example with glibc:

    #define _GNU_SOURCE
    #include <fenv.h>
    
    volatile double x = 1.0;
    volatile double y;
    volatile double quotient;
    
    int
    main(void)
    {
      feenableexcept(FE_DIVBYZERO);
      quotient = x / y;
    }

As far as I understand it, overall support for trapping math is poor because not much code is trapping-aware. It would be quite annoying if JSON parsing results in SIGFPE due to an Inexect trap, for example.