1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)isinf.3 8.2 (Berkeley) 01/29/94 7.\" 8.Dd 9.Dt ISINF 3 10.Os 11.Sh NAME 12.Nm isinf , 13.Nm isnan 14.Nd test for infinity or not-a-number 15.Sh SYNOPSIS 16.Ft int 17.Fn isinf double 18.Ft int 19.Fn isnan double 20.Sh DESCRIPTION 21The 22.Fn isninf 23function 24returns 1 if the number is 25.Dq \\*(If , 26otherwise 0. 27.Pp 28The 29.Fn isnan 30function 31returns 1 if the number is 32.Dq not-a-number , 33otherwise 0. 34.Sh SEE ALSO 35.Xr math 3 36.Rs 37.%T "IEEE Standard for Binary Floating-Point Arithmetic" 38.%Q ANSI 39.%R Std 754-1985 40.Re 41.Sh BUGS 42Neither the 43.Tn VAX 44nor the Tahoe floating point have distinguished values 45for either infinity or not-a-number. 46These routines always return 0 on those architectures. 47