This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
#include <wchar.h> wchar_t *wcstok(wchar_t *restrict ws1, const wchar_t *restrict ws2, wchar_t **restrict ptr);
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.1-2017 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().
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.
No errors are defined.
The following sections are informative.
The Base Definitions volume of POSIX.1-2017, <wchar.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
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