NAME
isinf() — floating-point test for infinity
SYNOPSIS
#include <math.h>
int isinf(
floating-type
x);
DESCRIPTION
The
isinf()
macro determines whether its argument value is an infinity.
The macro can be used with either
double
or
float
arguments.
The ISO/ANSI C committee has approved the
isinf()
macro for inclusion in the C9X draft standard.
To use this 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.
The
isinf()
macro replaces the
isinf()
and
isinff()
functions, which are obsolete and are no longer supported.
RETURN VALUE
The
isinf()
macro returns a nonzero value if
x
is
±INFINITY.
Otherwise it returns zero.
EXAMPLE
Take certain actions if
x
is infinity:
#include <math.h>
/*...*/
float x;
/*...*/
if (isinf(x))
/*...*/
ERRORS
No errors are defined.
