Header File 

float.h 

Category 

Math Routines 

Prototype 

int _fpclass(double d); 

int _fpclassl(long double ld); 

Description 

Returns an integer value representing the type (class) of an IEEE real for doubles. This value contains information on the floating-point class of the argument. 

_fpclassl is the long double version; it takes a long double argument and returns the type (class) of an IEEE real for long doubles. 

Return Value 

Returns an integer value that indicates the floating-point class of its argument. The possible values, which are listed in the table below, are defined in FLOAT.H. 

Portability