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.\" $FreeBSD$ 34.\" 35.Dd February 28, 2009 36.Dt STRLEN 3 37.Os 38.Sh NAME 39.Nm strlen , 40.Nm strnlen 41.Nd find length of string 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft size_t 47.Fn strlen "const char *s" 48.Ft size_t 49.Fn strnlen "const char *s" "size_t maxlen" 50.Sh DESCRIPTION 51The 52.Fn strlen 53function 54computes the length of the string 55.Fa s . 56The 57.Fn strnlen 58function attempts to compute the length of 59.Fa s , 60but never scans beyond the first 61.Fa maxlen 62bytes of 63.Fa s . 64.Sh RETURN VALUES 65The 66.Fn strlen 67function 68returns 69the number of characters that precede the 70terminating 71.Dv NUL 72character. 73The 74.Fn strnlen 75function returns either the same result as 76.Fn strlen 77or 78.Fa maxlen , 79whichever is smaller. 80.Sh SEE ALSO 81.Xr string 3 , 82.Xr wcslen 3 , 83.Xr wcswidth 3 84.Sh STANDARDS 85The 86.Fn strlen 87function 88conforms to 89.St -isoC . 90The 91.Fn strnlen 92function conforms to 93.St -p1003.1-2008 . 94