wcstok - split wide-character string into tokens
Standard C library (libc
, -lc
)
#include <wchar.h>
wchar_t *wcstok(wchar_t *restrict wcs, const wchar_t *restrict delim,
wchar_t **restrict ptr);
The wcstok() function is the wide-character
equivalent of the strtok(3) function, with an added
argument to make it multithread-safe. It can be used to split a
wide-character string wcs
into tokens, where a token is defined
as a substring not containing any wide-characters from
delim
.
The search starts at wcs
, if wcs
is not NULL, or at
*ptr
, if wcs
is NULL. First, any delimiter
wide-characters are skipped, that is, the pointer is advanced beyond any
wide-characters which occur in delim
. If the end of the
wide-character string is now reached, wcstok() returns
NULL, to indicate that no tokens were found, and stores an appropriate
value in *ptr
, so that subsequent calls to
wcstok() will continue to return NULL. Otherwise, the
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
delim
with a null wide character (L'\0'), and it updates
*ptr
so that subsequent calls will continue searching after the
end of recognized token.
The wcstok() function returns a pointer to the next token, or NULL if no further token was found.
The following code loops over the tokens contained in a wide-character string.
wchar_t *wcs = ...;
wchar_t *token;
wchar_t *state;
for (token = wcstok(wcs, L" \t\n", &state);
token != NULL;
token = wcstok(NULL, L" \t\n", &state)) {
...
}
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
wcstok() |
Thread safety | MT-Safe |
C11, POSIX.1-2008.
POSIX.1-2001, C99.
The original wcs
wide-character string is destructively
modified during the operation.