wcstok, wcstok_s

• If str ! = NULL , the call is treated as the first call to wcstok for this particular wide string. The function searches for the first wide character which is not contained in delim .

• If no such wide character was found, there are no tokens in str at all, and the function returns a null pointer.
• If such wide character was found, it is the beginning of the token . The function then searches from that point on for the first wide character that is contained in delim .

• If no such wide character was found, str has only one token, and future calls to wcstok will return a null pointer
• If such wide character was found, it is replaced by the null wide character L ' \0 ' and the parser state (typically a pointer to the following wide character) is stored in the user-provided location * ptr .

• The function then returns the pointer to the beginning of the token

• If str == NULL , the call is treated as a subsequent call to wcstok : the function continues from where it left in the previous invocation with the same * ptr . The behavior is the same as if the pointer to the wide character that follows the last detected token is passed as str .

Parameters

Return value

Returns pointer to the beginning of the next token or null pointer if there are no more tokens.

Note

This function is destructive: it writes the L ' \0 ' characters in the elements of the string str . In particular, a wide string literal cannot be used as the first argument of wcstok .

Unlike strtok , wcstok does not update static storage: it stores the parser state in the user-provided location.

Unlike most other tokenizers, the delimiters in wcstok can be different for each subsequent token, and can even depend on the contents of the previous tokens.

The implementation of wcstok_s in the Windows CRT is incompatible with the C standard, it is merely an alias for wcstok .

Example

#include <stdio.h>
#include <wchar.h>
 
int main(void)
{
    wchar_t input[] = L"A bird came down the walk";
    printf("Parsing the input string '%ls'\n", input);
    wchar_t* buffer;
    wchar_t* token = wcstok(input, L" ", &buffer);
    while (token)
    {
        printf("%ls\n", token);
        token = wcstok(NULL, L" ", &buffer);
    }
 
    printf("Contents of the input string now: '");
    for (size_t n = 0; n < sizeof input / sizeof *input; ++n)
        input[n] ? printf("%lc", input[n]) : printf("\\0");
    puts("'");
}

Parsing the input string 'A bird came down the walk'
A
bird
came
down
the
walk
Contents of the input string now: 'A\0bird\0came\0down\0the\0walk\0'

References

See also