NAME

fpclassify — classify real floating type

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <math.h>

int
fpclassify(real-floating x);

DESCRIPTION

The fpclassify() macro performs classification of its argument x. An argument represented in a format wider than its semantic type is converted to its semantic type first. The classification is then based on the type of the argument.

IEEE 754

FP_INFINITE: infinity, either positive or negative
FP_NAN: not-a-number (“NaN”)
FP_NORMAL: normal
FP_SUBNORMAL: subnormal
FP_ZERO: zero

VAX

FP_ROP: reserved operand (“ROP”)
FP_DIRTYZERO: dirty zero
FP_NORMAL: finite
FP_ZERO: true zero

RETURN VALUES

The fpclassify() macro returns the value of the number classification macro appropriate to its argument x as described above.

ERRORS

No errors are defined.

STANDARDS

The fpclassify() macro conforms to ISO/IEC 9899:1999 (“ISO C99”).