std::wcstok
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Null-terminated wide strings
(C++11)
(C++11)(C++11)
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::wcstokfor 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::wcstokwill return a null pointer. - If such wide character was found, it is replaced by the null wide character L'0円' and the parser state (typically a pointer to the following wide character) is stored in the user-provided location *ptr.
- If no such wide character was found, str has only one token, and future calls to
- 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.
- If str != nullptr, the call is treated as the first call to
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円' 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
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
[edit] See also
C documentation for wcstok