Why does wide file-stream in C++ narrow written data by default?

Question

Honestly, I just don\'t get the following design decision in C++ Standard library. When writing wide characters to a file, the wofstream converts wchar_t<

Answer 1

Check this out: Class basic_filebuf

You can alter the default behavior by setting a wide char buffer, using pubsetbuf. Once you did that, the output will be wchar_t and not char.

In other words for your example you will have:

wofstream file(L"Test.txt", ios_base::binary); //binary is important to set!  
wchar_t buffer[128];  
file.rdbuf()->pubsetbuf(buffer, 128);  
file.put(0xFEFF); //this is the BOM flag, UTF16 needs this, but mirosoft's UNICODE doesn't, so you can skip this line, if any.  
file << someString; // the output file will consist of unicode characters! without the call to pubsetbuf, the out file will be ANSI (current regional settings)