HP-UX Reference (11i v1 05/09) - 3 Library Functions A-M (vol 6)

i
isfinite(3M) isfinite(3M)
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 nor-
malized, 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 stan-
dard. The
isfinite() macro implements the finite() function recommended by the IEEE-754 stan-
dard 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))
/*...*/
SEE ALSO
fpclassify(3M), isinf(3M), isnan(3M), isnormal(3M), signbit(3M), math(5).
Section 3−−502 Hewlett-Packard Company − 1 − HP-UX 11i Version 1: September 2005