'\" 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 2023-07-20 "Linux man-pages 6.05.01"
.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).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR wcstok ()
T}	Thread safety	MT-Safe
.TE
.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)