Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
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$FreeBSD: src/lib/libc/gen/fpclassify.3,v 1.6 2005/01/27 05:46:16 das Exp $
.Dd $Mdocdate: November 10 2015 $ .Dt FPCLASSIFY 3 .Os .Sh NAME .Nm fpclassify , .Nm isfinite , .Nm isinf , .Nm isnan , .Nm isnormal , .Nm signbit , .Nm finite , .Nm finitef , .Nm isinff , .Nm isnanf .Nd classify a floating-point number .Sh SYNOPSIS n math.h .Ft int .Fn fpclassify "real-floating x" .Ft int .Fn isfinite "real-floating x" .Ft int .Fn isinf "real-floating x" .Ft int .Fn isnan "real-floating x" .Ft int .Fn isnormal "real-floating x" .Ft int .Fn signbit "real-floating x" .Sh DESCRIPTION The .Fn fpclassify macro takes an argument of .Fa x and returns one of the following manifest constants:
p l -tag -width "FP_SUBNORMALXXX" -offset indent -compact t Dv FP_INFINITE Indicates that .Fa x is an infinite number. t Dv FP_NAN Indicates that .Fa x is not a number (NaN). t Dv FP_NORMAL Indicates that .Fa x is a normalized number. t Dv FP_SUBNORMAL Indicates that .Fa x is a denormalized number. t Dv FP_ZERO Indicates that .Fa x is zero (0 or -0). .El
p The .Fn isfinite macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value.
p The .Fn isinf , .Fn isnan , and .Fn isnormal macros return non-zero if and only if .Fa x is an infinity, NaN, or a non-zero normalized number, respectively.
p The .Fn signbit macro takes an argument of .Fa x and returns non-zero if the value of its sign is negative, otherwise 0. .Sh SEE ALSO .Xr isgreater 3 .Sh STANDARDS The .Fn fpclassify , .Fn isfinite , .Fn isinf , .Fn isnan , .Fn isnormal , and .Fn signbit macros conform to .St -isoC-99 .
p The symbols .Fn isinff , and .Fn isnanf are provided as compatibility aliases to .Fn isinf , and .Fn isnan , respectively, and their uses are deprecated. Similarly, .Fn finite and .Fn finitef are deprecated versions of .Fn isfinite . .Sh HISTORY The .Fn fpclassify , .Fn isfinite , .Fn isinf , .Fn isnan , .Fn isnormal , and .Fn signbit macros were added in .Ox 4.4 . x 3 introduced .Fn isinf and .Fn isnan functions, which accepted .Vt double arguments; these have been superseded by the macros described above.