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std::wcstok

From cppreference.com
< cpp‎ | string‎ | wide
Defined in header <cwchar>
wchar_t* wcstok( wchar_t* str, const wchar_t* delim, wchar_t ** ptr);

Finds the next token in a null-terminated wide string pointed to by str. The separator characters are identified by null-terminated wide string pointed to by delim.

This function is designed to be called multiples times to obtain successive tokens from the same string.
  • If str != nullptr, the call is treated as the first call to std::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 std::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 == nullptr, the call is treated as a subsequent calls to std::wcstok: the function continues from where it left in 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.

Contents

[edit] Parameters

str - pointer to the null-terminated wide string to tokenize
delim - pointer to the null-terminated wide string identifying delimiters
ptr - pointer to an object of type wchar_t*, which is used by wcstok to store its internal state

[edit] Return value

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

[edit] 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 std::wcstok.

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

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

[edit] Example

#include <cwchar>
#include <iostream>
 
int main()
{
    wchar_t input[100] = L"A bird came down the walk";
    wchar_t* buffer;
    wchar_t* token = std::wcstok(input, L" ", &buffer);
    while (token) {
        std::wcout << token << '\n';
        token = std::wcstok(nullptr, L" ", &buffer);
    }
}

Output:

A
bird
came
down
the
walk

[edit] See also

finds the next token in a byte string
(function) [edit]
C documentation for wcstok