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Includes the Standard C library header <fenv.h> and adds the associated names to the std namespace.


#include <cfenv>


Including this header ensures that the names declared using external linkage in the Standard C library header are declared in the std namespace.

Constants and Types

#define FE_ALL_EXCEPT see below
#define FE_DIVBYZERO see below
#define FE_INEXACT see below
#define FE_INVALID see below
#define FE_OVERFLOW see below
#define FE_UNDERFLOW see below
#define FE_DOWNWARD see below
#define FE_TONEAREST see below
#define FE_TOWARDZERO see below
#define FE_UPWARD see below
#define FE_DFL_ENV see below

namespace std {
    using fenv_t = object type ;
    using fexcept_t = integer type ;


int feclearexcept(int except);
int fegetexceptflag(fexcept_t* pflag, int except);
int feraiseexcept(int except);
int fesetexceptflag(const fexcept_t* pflag, int except);
int fetestexcept(int except);
int fegetround();
int fesetround(int mode);
int fegetenv(fenv_t* penv);
int feholdexcept(fenv_t* penv);
int fesetenv(const fenv_t* penv);
int feupdateenv(const fenv_t* penv);

See also

Header Files Reference
C++ Standard Library Overview
Thread Safety in the C++ Standard Library