.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
.\"
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.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
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.\" References consulted:
.\"   GNU glibc-2 source code and manual
.\"   Dinkumware C library reference http://www.dinkumware.com/
.\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
.\"
.TH WCSNLEN 3  2021-03-22 "GNU" "Linux Programmer's Manual"
.SH NAME
wcsnlen \- determine the length of a fixed-size wide-character string
.SH SYNOPSIS
.nf
.B #include <wchar.h>
.PP
.BI "size_t wcsnlen(const wchar_t *" s ", size_t " maxlen );
.fi
.PP
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.PP
.BR wcsnlen ():
.nf
    Since glibc 2.10:
        _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:
        _GNU_SOURCE
.fi
.SH DESCRIPTION
The
.BR wcsnlen ()
function is the wide-character equivalent
of the
.BR strnlen (3)
function.
It returns the number of wide-characters in the string pointed to by
.IR s ,
not including the terminating null wide character (L\(aq\e0\(aq),
but at most
.I maxlen
wide characters (note: this parameter is not a byte count).
In doing this,
.BR wcsnlen ()
looks at only the first
.I maxlen
wide characters at
.I s
and never beyond
.IR s+maxlen .
.SH RETURN VALUE
The
.BR wcsnlen ()
function returns
.IR wcslen(s) ,
if that is less than
.IR maxlen ,
or
.I maxlen
if there is no null wide character among the
first
.I maxlen
wide characters pointed to by
.IR s .
.SH VERSIONS
The
.BR wcsnlen ()
function is provided in glibc since version 2.1.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.nh
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.BR wcsnlen ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH CONFORMING TO
POSIX.1-2008.
.SH SEE ALSO
.BR strnlen (3),
.BR wcslen (3)
.SH COLOPHON
This page is part of release 5.13 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.