get length of `wchar_t*` in c++

Question

Please, how can I find out the length of a variable of type wchar_t* in c++?

code example below:

wchar_t* dimObjPrefix = L"retro_";

I would like to find out how many characters dimObjPrefix contains

Solution 1

If you want to know the size of a wchar_t string (wchar_t *), you want to use wcslen(3):

size_t wcslen (const wchar_t *ws);

Solution 2

Assuming that you want to get the length of null terminated C style string, you have two options:

1. #include <cwchar> and use std::wcslen (dimObjPrefix);,
2. or #include <string> and use std::char_traits<wchar_t>::length (dimObjPrefix);.

Comments

[Joseph Quinsey]

Perhaps sizeof (wchar_t), or wchar_t x followed by sizeof x?

[Bertrand Marron]

@Joseph, it took me a long time to realize what you meant, I edited. Thank you. Sorry for the confusion.

[Joseph Quinsey]

Regarding sizeof(), neither K&R nor the ANSI Rationale give any reason for this idiosyncrasy about parentheses; does any SO reader happen to know?

[MSalters]

sizeof(type) versus sizeof expression. Now if e is an expression, then (e) is also an expression, so sizeof (expression) is implicitly also allowed.

[Mayur]

Is it safe to use wcslen?