ISINF(3) BSD Library Functions Manual ISINF(3)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 (posi‐
tive 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 infin‐
ity. Otherwise 0 is returned.
SEE ALSOfpclassify(3), isfinite(3), isnan(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”).
BSD March 5, 2004 BSD