fpclassify(3) BSD Library Functions Manual fpclassify(3)
NAME
fpclassify, isfinite, isinf, isnan, isnormal -- classify a floating-point
number
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
int
fpclassify(real-floating x);
int
isfinite(real-floating x);
int
isinf(real-floating x);
int
isnan(real-floating x);
int
isnormal(real-floating x);
DESCRIPTION
The fpclassify() macro takes an argument of x and returns one of the fol-
lowing manifest constants.
FP_INFINITE Indicates that x is an infinite number.
FP_NAN Indicates that x is not a number (NaN).
FP_NORMAL Indicates that x is a normalized number.
FP_SUBNORMAL Indicates that x is a denormalized number.
FP_ZERO Indicates that x is zero (0 or -0).
The isfinite() macro returns a non-zero value if and only if its argument
has a finite (zero, subnormal, or normal) value. The isinf(), isnan(),
and isnormal() macros return non-zero if and only if x is an infinity,
NaN, or a non-zero normalized number, respectively.
SEE ALSO
isgreater(3), math(3), signbit(3)
STANDARDS
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros
conform to ISO/IEC 9899:1999 (``ISO C99'').
HISTORY
3BSD introduced isinf() and isnan() functions, which accepted double
arguments; these have been superseded by the macros described above.
BSD December 11, 2006 BSD
Mac OS X 10.6 - Generated Thu Sep 17 20:19:51 CDT 2009