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.TH ISINF 3M "Nov 17, 2008" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
isinf \- test for infinity
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <math.h>

\fBint\fR \fBisinf\fR(\fBreal-floating\fR \fIx\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBisinf()\fR macro determines whether its argument value is an infinity
(positive or negative). First, an argument represented in a format wider than
its semantic type is converted to its semantic type. Then determination is
based on the type of the argument.
.SH RETURN VALUES
.sp
.LP
The \fBisinf()\fR macro returns a non-zero value if and only if its argument
has an infinite value.
.SH ERRORS
.sp
.LP
No errors are defined.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
tab(	) box;
cw(2.75i) |cw(2.75i)
lw(2.75i) |lw(2.75i)
.
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	MT-Safe
.TE

.SH SEE ALSO
.sp
.LP
.BR math.h (3HEAD),
.BR fpclassify (3M),
.BR isfinite (3M),
.BR isnan (3M),
.BR isnormal (3M),
.BR signbit (3M),
.BR attributes (7),
.BR standards (7)