NAME

wcstok — split a wide-character string into tokens

SYNOPSIS

#include <wchar.h>

wchar_t *wcstok(wchar_t *restrict ws1, const wchar_t *restrict ws2,
       wchar_t **restrict ptr);


DESCRIPTION

^[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2024 defers to the ISO C standard.

A sequence of calls to wcstok() shall break the wide-character string pointed to by ws1 into a sequence of tokens, each of which shall be delimited by a wide-character code from the wide-character string pointed to by ws2. The ptr argument points to a caller-provided wchar_t pointer into which the wcstok() function shall store information necessary for it to continue scanning the same wide-character string.

The first call in the sequence has ws1 as its first argument, and is followed by calls with a null pointer as their first argument. The separator string pointed to by ws2 may be different from call to call.

The first call in the sequence shall search the wide-character string pointed to by ws1 for the first wide-character code that is not contained in the current separator string pointed to by ws2. If no such wide-character code is found, then there are no tokens in the wide-character string pointed to by ws1 and wcstok() shall return a null pointer. If such a wide-character code is found, it shall be the start of the first token.

The wcstok() function shall then search from there for a wide-character code that is contained in the current separator string. If no such wide-character code is found, the current token extends to the end of the wide-character string pointed to by ws1, and subsequent searches for a token shall return a null pointer. If such a wide-character code is found, it shall be overwritten by a null wide character, which terminates the current token. The wcstok() function shall save a pointer to the following wide-character code, from which the next search for a token shall start.

Each subsequent call, with a null pointer as the value of the first argument, shall start searching from the saved pointer and behave as described above.

The implementation shall behave as if no function calls wcstok().

^[CX] The wcstok() function shall not change the setting of errno on valid input.

RETURN VALUE

Upon successful completion, the wcstok() function shall return a pointer to the first wide-character code of a token. Otherwise, if there is no token, wcstok() shall return a null pointer.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

XBD <wchar.h>

CHANGE HISTORY

First released in Issue 4.

Issue 5

Aligned with ISO/IEC 9899:1990/Amendment 1:1995 (E). Specifically, a third argument is added to the definition of wcstok() in the SYNOPSIS.

Issue 6

The wcstok() prototype is updated for alignment with the ISO/IEC 9899:1999 standard.

Issue 8

Austin Group Defect 448 is applied, adding a requirement that wcstok() does not change the setting of errno on valid input.