Question

I am using Visual C++ 2010, and the code is:

#include "stdafx.h"
#include <stdio.h> 

int _tmain(int argc, _TCHAR* argv[]) { 
    printf("step 0: %s\n", argv[0]);
    int d;
    scanf("%d",&d);
    return 0;
}

When I choose _UNICODE, the output is “D”,
and when I choose _MBCS, it works well and the output is “D:\VCTest\c1006.exe”

Why is it wrong in _UNICODE?
How can I use the same code for both _UNICODE and _MBCS ?

Answer 1

When compiling a Unicode project, _TCHAR is wchar_t, not char.

The %s format specifier expects its corresponding argument to be a char const*; you are passing a wchar_t*, thus the unexpected result.

You can use _tprintf, which will select the right printf function (printf or wprintf) based on whether the project is being built as ANSI or Unicode. If you want to use printf, you can use the %ls format specifier for wide strings, but then you have to use different format strings depending on whether the project is built as ANSI or Unicode.

Alternatively, just use Unicode and don’t use _TCHAR and friends at all.