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.Va x 52and returns one of the following manifest constants. 53.Bl -tag -width ".Dv FP_SUBNORMAL" 54.It Dv FP_INFINITE 55Indicates that 56.Va x 57is an infinite number. 58.It Dv FP_NAN 59Indicates that 60.Va x 61is not a number (NaN). 62.It Dv FP_NORMAL 63Indicates that 64.Va x 65is a normalized number. 66.It Dv FP_SUBNORMAL 67Indicates that 68.Va x 69is a denormalized number. 70.It Dv FP_ZERO 71Indicates that 72.Va 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. The 80.Fn isinf , 81.Fn isnan , 82and 83.Fn isnormal 84macros return non-zero if and only if 85.Va x 86is an infinity, NaN, 87or a non-zero normalized number, respectively. 88.Pp 89The symbol 90.Fn isnanf 91is provided as an alias to 92.Fn isnan 93for compatibility, and its use is deprecated. 94.Sh SEE ALSO 95.Xr isgreater 3 , 96.Xr math 3 , 97.Xr signbit 3 98.Sh STANDARDS 99The 100.Fn fpclassify , 101.Fn isfinite , 102.Fn isinf , 103.Fn isnan , 104and 105.Fn isnormal 106macros conform to 107.St -isoC-99 . 108.Sh HISTORY 109The 110.Fn fpclassify , 111.Fn isfinite , 112.Fn isinf , 113.Fn isnan , 114and 115.Fn isnormal 116macros were added in 117.Fx 5.1 . 118.Bx 3 119introduced 120.Fn isinf 121and 122.Fn isnan 123functions, which accepted 124.Ft double 125arguments; these have been superseded by the macros 126described above. 127.Sh BUGS 128By default, the DEC Alpha architecture does not support IEEE rounding. 129See the compiler documentation for additional details. 130