fenv.h

Go to the documentation of this file.

#pragma once
 
#include_next <fenv.h>
 
#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;
}
 
#endif // defined(__APPLE__) && defined(__MACH__)