HP-UX Reference (11i v3 07/02) - 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 argument must be of floating type, and classification is based on the
type of the argument. For HP Integrity servers, the argument can be any floating type. For PA-RISC, 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
HP-UX 11i Version 3: February 2007 − 1 − Hewlett-Packard Company 699