FreeBSD manual
download PDF document: finite.3.pdf
FPCLASSIFY(3) FreeBSD 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
following 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.
The symbol isnanf() is provided as an alias to isnan() for compatibility,
and its use is deprecated. Similarly, finite() and finitef() are
deprecated versions of isfinite().
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
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros