std::wcstok
Defined in header <cwchar>
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wchar_t* wcstok( wchar_t* str, const wchar_t* delim, wchar_t ** ptr); |
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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 != NULL, 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 indelim
.
- 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 tostd::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.
- If no such wide character was found,
- The function then returns the pointer to the beginning of the token
- If no such wide character was found, there are no tokens in
- If str == NULL, 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 != NULL, the call is treated as the first call to
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
finds the next token in a byte string (function) |