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.\" 4. 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.\" $FreeBSD$ 34.\" 35.Dd February 28, 2009 36.Dt STRLEN 3 37.Os 38.Sh NAME 39.Nm strlen, strnlen 40.Nd find length of string 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In string.h 45.Ft size_t 46.Fn strlen "const char *s" 47.Ft size_t 48.Fn strnlen "const char *s" "size_t maxlen" 49.Sh DESCRIPTION 50The 51.Fn strlen 52function 53computes the length of the string 54.Fa s . 55The 56.Fn strnlen 57function attempts to compute the length of 58.Fa s , 59but never scans beyond the first 60.Fa maxlen 61bytes of 62.Fa s . 63.Sh RETURN VALUES 64The 65.Fn strlen 66function 67returns 68the number of characters that precede the 69terminating 70.Dv NUL 71character. 72The 73.Fn strnlen 74function returns either the same result as 75.Fn strlen 76or 77.Fa maxlen , 78whichever is smaller. 79.Sh SEE ALSO 80.Xr string 3 , 81.Xr wcslen 3 , 82.Xr wcswidth 3 83.Sh STANDARDS 84The 85.Fn strlen 86function 87conforms to 88.St -isoC . 89The 90.Fn strnlen 91function conforms to 92.St -p1003.1-2008 . 93