NAME
isinf —
test for infinity
LIBRARY
library “libc”
SYNOPSIS
#include
<math.h>
int
isinf(real-floating
x);
DESCRIPTION
Theisinf()
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.
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”).
CAVEATS
On VAX the isinf() function always returns
0, as the architecture doesn't have a representation for infinity.