'\" t
.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.\" 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
.\"   ISO/IEC 9899:1999
.\"
.TH wcstok 3 2023-03-30 "Linux man-pages 6.04"
.SH NAME
wcstok \- split wide-character string into tokens
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.B #include <wchar.h>
.PP
.BI "wchar_t *wcstok(wchar_t *restrict " wcs \
", const wchar_t *restrict " delim ,
.BI "                wchar_t **restrict " ptr );
.fi
.SH DESCRIPTION
The
.BR wcstok ()
function is the wide-character equivalent of the
.BR strtok (3)
function,
with an added argument to make it multithread-safe.
It can be used
to split a wide-character string
.I wcs
into tokens, where a token is
defined as a substring not containing any wide-characters from
.IR delim .
.PP
The search starts at
.IR wcs ,
if
.I wcs
is not NULL,
or at
.IR *ptr ,
if
.I wcs
is NULL.
First, any delimiter wide-characters are skipped, that is, the
pointer is advanced beyond any wide-characters which occur in
.IR delim .
If the end of the wide-character string is now
reached,
.BR wcstok ()
returns NULL, to indicate that no tokens
were found, and stores an appropriate value in
.IR *ptr ,
so that subsequent calls to
.BR wcstok ()
will continue to return NULL.
Otherwise, the
.BR wcstok ()
function recognizes the beginning of a token
and returns a pointer to it, but before doing that, it zero-terminates the
token by replacing the next wide-character which occurs in
.I delim
with
a null wide character (L\[aq]\e0\[aq]),
and it updates
.I *ptr
so that subsequent calls will
continue searching after the end of recognized token.
.SH RETURN VALUE
The
.BR wcstok ()
function returns a pointer to the next token,
or NULL if no further token was found.
.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 wcstok ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH STANDARDS
C11, POSIX.1-2008.
.SH HISTORY
POSIX.1-2001, C99.
.SH NOTES
The original
.I wcs
wide-character string is destructively modified during
the operation.
.SH EXAMPLES
The following code loops over the tokens contained in a wide-character string.
.PP
.EX
wchar_t *wcs = ...;
wchar_t *token;
wchar_t *state;
for (token = wcstok(wcs, L" \et\en", &state);
    token != NULL;
    token = wcstok(NULL, L" \et\en", &state)) {
    ...
}
.EE
.SH SEE ALSO
.BR strtok (3),
.BR wcschr (3)