How can I get the byte size of std :: wstring?

Question

I use std :: wstring as a Unicode style string. Now I want to get the wstring byte size. If I use the size () method for wstring, I just get the total number of characters in my wstring. But the byte should be size () * 2. Is there an official way to get this byte size? I do not want to use size () * 2 in my program .....

I want to use in RegSetValueExW as the last parameter.

Answer 1

Use str.size() * sizeof(wchar_t) or equivalent.

In fact, I can not think of any other platform besides Windows, which has 2 bytes wchar_t , 4 bytes are much more common.

Answer 2

Why not:

 ( str.size() * sizeof(wchar_t) ) ; 

Or:

 ( str.size() * sizeof(std::wstring::traits_type::char_type) ) ; 

Answer 3

 std::wstring s = L"Howdy, world!"; //... std::size_t bytes_count = s.size() * sizeof s[0]; 

Answer 4

You can use the wcslen function

MSDN Link: http://msdn.microsoft.com/en-us/library/78zh94ax.aspx

Linux: http://linux.die.net/man/3/wcslen