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+.\" Copyright (c) 1990, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" Chris Torek and the American National Standards Committee X3,
+.\" on Information Processing Systems.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.Dd April 3, 2022
+.Dt STRLEN 3
+.Os
+.Sh NAME
+.Nm strlen ,
+.Nm strnlen
+.Nd find length of string
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In string.h
+.Ft size_t
+.Fn strlen "const char *s"
+.Ft size_t
+.Fn strnlen "const char *s" "size_t maxlen"
+.Sh DESCRIPTION
+The
+.Fn strlen
+function
+computes the length of the string
+.Fa s .
+The
+.Fn strnlen
+function attempts to compute the length of
+.Fa s ,
+but never scans beyond the first
+.Fa maxlen
+bytes of
+.Fa s .
+.Sh RETURN VALUES
+The
+.Fn strlen
+function
+returns
+the number of characters that precede the
+terminating
+.Dv NUL
+character.
+The
+.Fn strnlen
+function returns either the same result as
+.Fn strlen
+or
+.Fa maxlen ,
+whichever is smaller.
+.Sh SEE ALSO
+.Xr string 3 ,
+.Xr wcslen 3 ,
+.Xr wcswidth 3
+.Sh STANDARDS
+The
+.Fn strlen
+function
+conforms to
+.St -isoC .
+The
+.Fn strnlen
+function conforms to
+.St -p1003.1-2008 .
+.Sh HISTORY
+The
+.Fn strlen
+function first appeared in the Programmer's Workbench (PWB/UNIX)
+and was ported to
+.At v7 .
+The
+.Fn strnlen
+function first appeared in
+.Fx 8.0 ,
+.Ox 4.8 ,
+and
+.Nx 6.0 .