std::wcstok(3)

NAME
std::wcstok - std::wcstok

Synopsis
   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.

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

Return value
   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 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.

Example
// Run this code
 #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

See also
   strtok finds the next token in a byte string
          (function)