fenv.h File Reference

#include <float.h>

Go to the source code of this file.

Classes
struct	fenv_t

Macros
#define	_FENV
#define	FE_INEXACT   _SW_INEXACT /* _EM_INEXACT 0x00000001 inexact (precision) */
#define	FE_UNDERFLOW   _SW_UNDERFLOW /* _EM_UNDERFLOW 0x00000002 underflow */
#define	FE_OVERFLOW   _SW_OVERFLOW /* _EM_OVERFLOW 0x00000004 overflow */
#define	FE_DIVBYZERO   _SW_ZERODIVIDE /* _EM_ZERODIVIDE 0x00000008 zero divide */
#define	FE_INVALID   _SW_INVALID /* _EM_INVALID 0x00000010 invalid */
#define	FE_ALL_EXCEPT   (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
#define	FE_DFL_ENV   (&_Fenv0)
#define	FE_TONEAREST   0x0000
#define	FE_UPWARD   0x0100
#define	FE_DOWNWARD   0x0200
#define	FE_TOWARDZERO   0x0300
#define	FE_ROUND_MASK   0x0300
#define	__DBL_BIG   1e+300 /* may raise inexact too */

Typedefs
typedef unsigned long	fexcept_t
typedef struct fenv_t	fenv_t

Functions
_CRTIMP int __cdecl	fegetenv (_Inout_ fenv_t *)
_CRTIMP int __cdecl	fesetenv (_In_ const fenv_t *)
_CRTIMP int __cdecl	feclearexcept (_In_ int)
_CRTIMP int __cdecl	feholdexcept (_Inout_ fenv_t *)
_CRTIMP int __cdecl	fetestexcept (_In_ int)
_CRTIMP int __cdecl	fegetexceptflag (_Inout_ fexcept_t *, _In_ int)
_CRTIMP int __cdecl	fesetexceptflag (_In_ const fexcept_t *, _In_ int)
	__declspec (selectany) extern const fenv_t _Fenv0
_CRTIMP int __cdecl	fegetround (void)
_CRTIMP int __cdecl	fesetround (_In_ int)
__inline int __CRTDECL	feraiseexcept (_In_ int _Except)
__inline int __CRTDECL	feupdateenv (_In_ const fenv_t *_Penv)

Macro Definition Documentation

#define __DBL_BIG   1e+300 /* may raise inexact too */

#define _FENV

#define FE_ALL_EXCEPT   (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)

#define FE_DFL_ENV   (&_Fenv0)

#define FE_DIVBYZERO   _SW_ZERODIVIDE /* _EM_ZERODIVIDE 0x00000008 zero divide */

#define FE_DOWNWARD   0x0200

#define FE_INEXACT   _SW_INEXACT /* _EM_INEXACT 0x00000001 inexact (precision) */

#define FE_INVALID   _SW_INVALID /* _EM_INVALID 0x00000010 invalid */

#define FE_OVERFLOW   _SW_OVERFLOW /* _EM_OVERFLOW 0x00000004 overflow */

#define FE_ROUND_MASK   0x0300

#define FE_TONEAREST   0x0000

#define FE_TOWARDZERO   0x0300

#define FE_UNDERFLOW   _SW_UNDERFLOW /* _EM_UNDERFLOW 0x00000002 underflow */

#define FE_UPWARD   0x0100

Typedef Documentation

typedef struct fenv_t fenv_t

typedef unsigned long fexcept_t

Function Documentation

__declspec

(

selectany

)

const

_CRTIMP int __cdecl feclearexcept

(

_In_

int

)

_CRTIMP int __cdecl fegetenv

(

_Inout_ fenv_t *

)

_CRTIMP int __cdecl fegetexceptflag	(	_Inout_ fexcept_t *	,
		_In_	int
	)

_CRTIMP int __cdecl fegetround

(

void

)

_CRTIMP int __cdecl feholdexcept

(

_Inout_ fenv_t *

)

__inline int __CRTDECL feraiseexcept

(

_In_ int

_Except

)

{
    #define __DBL_BIG  1e+300  /* may raise inexact too */

    static struct
    {
        int _Except_Val;
        double _Num, _Denom;
    } const _Table[] = 
    {  /* raise exception by evaluating num / denom */
        {FE_INVALID, 0.0, 0.0},
        {FE_DIVBYZERO, 1.0, 0.0},
        {FE_OVERFLOW, __DBL_BIG, 1.0 / __DBL_BIG},
        {FE_UNDERFLOW, 1.0 / __DBL_BIG, __DBL_BIG},
        {FE_INEXACT, 2.0, 3.0}
    };

    fexcept_t _Flags = 0;
    double _Ans = 0.0;
    int _N;

    if ((_Except &= FE_ALL_EXCEPT) == 0)
    {
        return 0;
    }

    /* get the current status flags */
    fegetexceptflag(&_Flags, FE_ALL_EXCEPT);

    _Except &= ~_Flags;
    _Flags |= _Except;

    /* set the new status flags */
    fesetexceptflag(&_Flags, FE_ALL_EXCEPT);

    /* raise the exceptions not masked */
    for (_N = 0; _N < sizeof(_Table) / sizeof(_Table[0]); ++_N)
    {
        if ((_Except & _Table[_N]._Except_Val) != 0)
        {
            _Ans = _Table[_N]._Num / _Table[_N]._Denom;
        }
    }

    return 0;
}

_CRTIMP int __cdecl fesetenv

(

_In_ const fenv_t *

)

_CRTIMP int __cdecl fesetexceptflag	(	_In_ const fexcept_t *	,
		_In_	int
	)

_CRTIMP int __cdecl fesetround

(

_In_

int

)

_CRTIMP int __cdecl fetestexcept

(

_In_

int

)

__inline int __CRTDECL feupdateenv

(

_In_ const fenv_t *

_Penv

)

{
    int _Except = fetestexcept(FE_ALL_EXCEPT);

    if (fesetenv(_Penv) != 0 || feraiseexcept(_Except) != 0)
    {
        return 1;
    }

    return 0;
}