Find length of std::wstring
c++, unicode, winapi, wstring
Solution
`std::wstring::length()` will give you the number of characters, where character is defined as the atomic unit of the `wstring` object, i.e. a `wchar`. This is what the Standard means when it refers to `characters` (see this post for some more details on the use of the word in the Standard).
However, when it comes to Unicode characters, whether one `wchar` corresponds to one Unicode character depends on the encoding used inside the `wstring`. If UTF-16 is used, which is often (but not necessarily) the case, one `wchar` will correspond to one Unicode character only for the base multilingual plane (i.e. all character sets derived from ISO-8859 as well as most of the commonly used CJK characters, but not some of the more exotic (e.g. classical Chinese) characters)(*). If you want to get the character count right for all Unicode characters in that case, you need to use a Unicode-aware library (e.g. ICU), or code it yourself.
(*)There are additional problems if combining characters are used, as @一二三 points out correctly. Counting those correctly is also best done using appropriate libraries.
Problem
How can I determine the length(number of characters) in a `std::wstring`? Using `myStr.length()` gives the byte size(I think) but its not the number of characters. Do I need to create my own function to find the number of characters or is there a native C++ way or a native WinAPI way?