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\" @(#)isinf.3 8.2 (Berkeley) 1/29/94
\"
Dd September 27, 2017
Dt ISINF 3
Os
Sh NAME
Nm isinf
Nd test for infinity
Sh LIBRARY
Lb libc
Sh SYNOPSIS
In math.h
Ft int
Fn isinf "real-floating x"
Sh DESCRIPTION
The
Fn isinf
macro determines whether its argument
Fa 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.
Sh RETURN VALUES
The
Fn isinf
macro returns a non-zero value if the value of
Fa x
is an infinity.
Otherwise 0 is returned.
Sh SEE ALSO
Xr fpclassify 3 ,
Xr isfinite 3 ,
Xr isinff 3 ,
Xr isnan 3 ,
Xr isnanf 3 ,
Xr isnormal 3 ,
Xr math 3 ,
Xr signbit 3
Rs
%T "IEEE Standard for Binary Floating-Point Arithmetic"
%Q ANSI
%R Std 754-1985
Re
Sh STANDARDS
The
Fn isinf
macro conforms to
St -isoC-99 .
Sh CAVEATS
On VAX the
Fn isinf
function always returns 0,
as the architecture doesn't have a representation for infinity.
