1.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd February 12, 2003 28.Dt FPCLASSIFY 3 29.Os 30.Sh NAME 31.Nm fpclassify , isfinite , isinf , isnan , isnormal 32.Nd "classify a floating-point number" 33.Sh LIBRARY 34.Lb libc 35.Sh SYNOPSIS 36.In math.h 37.Ft int 38.Fn fpclassify "real-floating x" 39.Ft int 40.Fn isfinite "real-floating x" 41.Ft int 42.Fn isinf "real-floating x" 43.Ft int 44.Fn isnan "real-floating x" 45.Ft int 46.Fn isnormal "real-floating x" 47.Sh DESCRIPTION 48The 49.Fn fpclassify 50macro takes an argument of 51.Fa x 52and returns one of the following manifest constants. 53.Bl -tag -width ".Dv FP_SUBNORMAL" 54.It Dv FP_INFINITE 55Indicates that 56.Fa x 57is an infinite number. 58.It Dv FP_NAN 59Indicates that 60.Fa x 61is not a number (NaN). 62.It Dv FP_NORMAL 63Indicates that 64.Fa x 65is a normalized number. 66.It Dv FP_SUBNORMAL 67Indicates that 68.Fa x 69is a denormalized number. 70.It Dv FP_ZERO 71Indicates that 72.Fa x 73is zero (0 or \-0). 74.El 75.Pp 76The 77.Fn isfinite 78macro returns a non-zero value if and only if its argument has 79a finite (zero, subnormal, or normal) value. 80The 81.Fn isinf , 82.Fn isnan , 83and 84.Fn isnormal 85macros return non-zero if and only if 86.Fa x 87is an infinity, NaN, 88or a non-zero normalized number, respectively. 89.Pp 90The symbol 91.Fn isnanf 92is provided as an alias to 93.Fn isnan 94for compatibility, and its use is deprecated. 95.Sh SEE ALSO 96.Xr isgreater 3 , 97.Xr math 3 , 98.Xr signbit 3 99.Sh STANDARDS 100The 101.Fn fpclassify , 102.Fn isfinite , 103.Fn isinf , 104.Fn isnan , 105and 106.Fn isnormal 107macros conform to 108.St -isoC-99 . 109.Sh HISTORY 110The 111.Fn fpclassify , 112.Fn isfinite , 113.Fn isinf , 114.Fn isnan , 115and 116.Fn isnormal 117macros were added in 118.Fx 5.1 . 119.Bx 3 120introduced 121.Fn isinf 122and 123.Fn isnan 124functions, which accepted 125.Vt double 126arguments; these have been superseded by the macros 127described above. 128.Sh BUGS 129By default, the DEC Alpha architecture does not support IEEE rounding. 130See the compiler documentation for additional details. 131