.\"	$NetBSD: fpclassify.3,v 1.3 2008/04/30 13:10:50 martin Exp $
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.\" by Klaus Klein.
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.Dd January 14, 2004
.Dt FPCLASSIFY 3
.Os
.Sh NAME
.Nm fpclassify
.Nd classify real floating type
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In math.h
.Ft int
.Fn fpclassify "real-floating x"
.Sh DESCRIPTION
The
.Fn fpclassify
macro performs classification of its argument
.Fa x .
An argument represented in a format wider than its semantic type is
converted to its semantic type first.
The classification is then based on the type of the argument.
.Ss IEEE 754
.Bl -tag -width "FP_SUBNORMALXXX" -compact -offset indent
.It Dv FP_INFINITE
infinity, either positive or negative
.It Dv FP_NAN
not-a-number
.Pq Dq NaN
.It Dv FP_NORMAL
normal
.It Dv FP_SUBNORMAL
subnormal
.It Dv FP_ZERO
zero
.El
.Ss VAX
.Bl -tag -width "FP_DIRTYZEROXXX" -compact -offset indent
.It Dv FP_ROP
reserved operand
.Pq Dq ROP
.It Dv FP_DIRTYZERO
dirty zero
.It Dv FP_NORMAL
finite
.It Dv FP_ZERO
true zero
.El
.Sh RETURN VALUES
The
.Fn fpclassify
macro returns the value of the number classification macro appropriate
to its argument
.Fa x
as described above.
.Sh ERRORS
No errors are defined.
.Sh SEE ALSO
.Xr isfinite 3 ,
.Xr isnormal 3 ,
.Xr math 3 ,
.Xr signbit 3
.Sh STANDARDS
The
.Fn fpclassify
macro conforms to
.St -isoC-99 .