Re: [boost] File operations: Win32 question [was Re: the first version of abstract path...]

From: Alan Bellingham (alan_at_[hidden])
Date: 2002-02-23 11:51:17

Beman Dawes <bdawes_at_[hidden]>:

>What does the wchar_t implementation look like?  There isn't a 
>GetFileAttributes overloaded for wchar_t; GetFileAttributes itself is 
>apparently Unicode enabled.  I guess that means the wstring path argument 
>has to be converted somehow before calling GetFileAttributes().

Actually, there is, sort of:

  <winbase.h>

  WINBASEAPI DWORD WINAPI GetFileAttributesA(IN LPCSTR lpFileName);
  WINBASEAPI DWORD WINAPI GetFileAttributesW(IN LPCWSTR lpFileName);

  #ifdef UNICODE
  #   define GetFileAttributes  GetFileAttributesW
  #else
  #   define GetFileAttributes  GetFileAttributesA
  #endif // !UNICODE

So to use narrow or wide strings explicitly, you use the A/W variants,
or to use them implicitly you do what I do, which is to apply a C++
solution:

  #undef GetFileAttributes
  inline DWORD GetFileAttributes(char const* FileName)
  {
     return GetFileAttributesA(FileName) ;
  }
  inline DWORD GetFileAttributes(wchar_t const* FileName)
  {
     return GetFileAttributesW(FileName) ;
  }

I dislike header files introducing macros for mixed or lower case
identifiers, because of the preprocessor's disregard for scope, so I
actually have a 40,000 line header file that undefines all such macros
introduced by the Win32 API headers and a shorter file that applies
inline overloads as above, on a case by case basis.