NAME
isinf —
test for infinity
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <math.h>
int
isinf(
real-floating
x);
DESCRIPTION
The
isinf() macro determines whether its argument
x is an infinity (positive or negative). An argument
represented in a format wider than its semantic type is converted to its
semantic type first. The determination is then based on the type of the
argument.
IEEE 754
It is determined whether the value of
x is an infinity.
VAX
Infinities are not supported.
RETURN VALUES
The
isinf() macro returns a non-zero value if the value of
x is an infinity. Otherwise 0 is returned.
SEE ALSO
fpclassify(3),
isfinite(3),
isinff(3),
isnan(3),
isnanf(3),
isnormal(3),
math(3),
signbit(3)
IEEE Standard for Binary Floating-Point
Arithmetic, Std 754-1985,
ANSI.
STANDARDS
The
isinf() macro conforms to
ISO/IEC
9899:1999 (“ISO C99”).