NAME
isfinite() — floating-point finiteness macro
SYNOPSIS
#include <math.h>
int isfinite(
floating-type
x);
DESCRIPTION
The
isfinite()
macro determines whether its argument has a finite value (zero,
denormalized, or normalized, and not infinite or NaN).
The macro can be used with either
double
or
float
arguments.
The ISO/ANSI C committee has approved the
isfinite()
macro for inclusion in the C9X draft standard.
The
isfinite()
macro implements the
finite()
function recommended by the IEEE-754 standard for
floating-point arithmetic.
To use the
isfinite()
macro, compile either with the default
-Ae
option or with the
-Aa
and
-D_HPUX_SOURCE
options. Make sure your program includes
<math.h>.
Link in the math library by specifying
-lm
on the compiler or linker command line.
RETURN VALUE
The
isfinite()
macro returns a nonzero value if and only if its argument has a finite
value.
ERRORS
No errors are defined.
EXAMPLE
Make sure a value is finite before continuing operations on it:
#include <math.h>
/*...*/
float x;
/*...*/
if (isfinite(x))
/*...*/
Printable version
