1.\" Copyright (c) 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" %sccs.include.redist.man% 9.\" 10.\" @(#)isdigit.3 5.3 (Berkeley) 10/23/91 11.\" 12.Dd 13.Dt ISDIGIT 3 14.Os 15.Sh NAME 16.Nm isdigit 17.Nd decimal-digit character test 18.Sh SYNOPSIS 19.Fd #include <ctype.h> 20.Ft int 21.Fn isdigit "int c"; 22.Sh DESCRIPTION 23The 24.Fn isdigit 25function tests for any decimal-digit character. 26.Sh RETURN VALUES 27The 28.Fn isdigit 29function returns zero if the character tests false and 30returns non-zero if the character tests true. 31.Sh SEE ALSO 32.Xr ctype 3 , 33.Xr ascii 7 34.Sh STANDARDS 35The 36.Fn isdigit 37function conforms to 38.St -ansiC . 39