1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)strlen.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/string/strlen.3,v 1.9 2009/04/07 13:42:53 trasz Exp $ 34.\" $DragonFly: src/lib/libc/string/strlen.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 35.\" 36.Dd April 23, 2009 37.Dt STRLEN 3 38.Os 39.Sh NAME 40.Nm strlen , 41.Nm strnlen 42.Nd find length of string 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.In string.h 47.Ft size_t 48.Fn strlen "const char *s" 49.Ft size_t 50.Fn strnlen "const char *s" "size_t maxlen" 51.Sh DESCRIPTION 52The 53.Fn strlen 54function 55computes the length of the string 56.Fa s . 57The 58.Fn strnlen 59function attempts to compute the length of 60.Fa s , 61but never scans beyond the first 62.Fa maxlen 63bytes of 64.Fa s . 65.Sh RETURN VALUES 66The 67.Fn strlen 68function 69returns 70the number of characters that precede the 71terminating 72.Dv NUL 73character. 74.Sh SEE ALSO 75.Xr string 3 , 76.Xr wcslen 3 , 77.Xr wcswidth 3 78.Sh STANDARDS 79The 80.Fn strlen 81function 82conforms to 83.St -isoC . 84The 85.Fn strnlen 86function conforms to 87.St -p1003.1-2008 . 88