HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

i
isfinite(3M) isfinite(3M)
NAME
isfinite(), finite() - 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 argument must be of floating type, and classification is based on
the type of the argument. On Itanium-based systems, the argument can be any floating type. On PA-
RISC systems, the argument must be either
double
or float.
The
isfinite() macro implements the finite() functionality recommended by the IEEE-754 stan-
dard for floating-point arithmetic.
USAGE
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. The
macro raises no floating-point exceptions.
ERRORS
No errors are defined.
EXAMPLES
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).
STANDARDS CONFORMANCE
isfinite(): ISO/IEC C99
Section 3−−562 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: September 2004