.\" Copyright (c) 1990, 1991, 1993
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.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
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.\"     @(#)strlen.3	8.1 (Berkeley) 6/4/93
.\"
.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