NAME
isinf() — floating-point test for infinity
SYNOPSIS
#include <math.h>
int isinf(floating-type x);
DESCRIPTION
The
isinf()
macro determines whether its argument is an infinity.
The argument must be of floating type, and classification
is based on the type of the argument. For Itanium(R)-based systems, the argument
can be any floating type. For PA-RISC, the argument must be
either
double
or
float.
The
isinf()
macro replaces the
isinf()
and
isinff()
functions, which are obsolete and are no longer supported.
USAGE
To use the
isinf()
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
isinf()
macro returns a nonzero value if
x
is
±INFINITY.
Otherwise, it returns zero.
The macro raises no floating-point exceptions.
ERRORS
No errors are defined.
EXAMPLES
Take certain actions if
x
is infinity:
#include <math.h>
/*...*/
float x;
/*...*/
if (isinf(x))
/*...*/
STANDARDS CONFORMANCE
isinf(): ISO/IEC C99
