ardupilot/libraries/AP_Common/missing/fenv.h

#pragma once

#include_next <fenv.h>

#ifndef HAVE_FEENABLEEXCEPT
#if defined(__APPLE__) && defined(__MACH__)

// Public domain polyfill for feenableexcept on OS X
// http://www-personal.umich.edu/~williams/archive/computation/fe-handling-example.c

inline int feenableexcept(unsigned int excepts)
{
    static fenv_t fenv;
    unsigned int new_excepts = excepts & FE_ALL_EXCEPT;
    // previous masks
    unsigned int old_excepts;

    if (fegetenv(&fenv)) {
        return -1;
    }
    old_excepts = fenv.__control & FE_ALL_EXCEPT;

    // unmask
    fenv.__control &= ~new_excepts;
    fenv.__mxcsr   &= ~(new_excepts << 7);

    return fesetenv(&fenv) ? -1 : old_excepts;
}

inline int fedisableexcept(unsigned int excepts)
{
    static fenv_t fenv;
    unsigned int new_excepts = excepts & FE_ALL_EXCEPT;
    // all previous masks
    unsigned int old_excepts;

    if (fegetenv(&fenv)) {
        return -1;
    }
    old_excepts = fenv.__control & FE_ALL_EXCEPT;

    // mask
    fenv.__control |= new_excepts;
    fenv.__mxcsr   |= new_excepts << 7;

    return fesetenv(&fenv) ? -1 : old_excepts;
}

#else
inline int feenableexcept(unsigned int excepts)
{
    #pragma STDC FENV_ACCESS ON
    fexcept_t flags;
    /* Save current exception flags. */
    fegetexceptflag(&flags, FE_ALL_EXCEPT);

    feclearexcept(FE_ALL_EXCEPT);   /* clear all fp exception conditions */
    return fesetexceptflag(&flags, excepts) != 0 ? -1 : flags; /* set new flags */

}

inline int fedisableexcept(unsigned int excepts)
{
    #pragma STDC FENV_ACCESS ON
    fexcept_t flags;
    /* Save current exception flags. */
    fegetexceptflag(&flags, FE_ALL_EXCEPT);

    feclearexcept(FE_ALL_EXCEPT);   /* clear all fp exception conditions */
    return fesetexceptflag(&flags, ~excepts) != 0 ? -1 : flags; /* set new flags */
}

#endif
#endif