如何获取％AppData％路径作为std :: string？

Question

I've read that one can use SHGetSpecialFolderPath(); to get the AppData path. However, it returns a TCHAR array. I need to have an std::string .

How can it be converted to an std::string ?

Update

I've read that it is possible to use getenv("APPDATA") , but that it is not available in Windows XP. I want to support Windows XP - Windows 10.

Answer 1

The T type means that SHGetSpecialFolderPath is a pair of functions:

• SHGetSpecialFolderPathA for Windows ANSI encoded char based text, and

• SHGetSpecialFolderPathW for UTF-16 encoded wchar_t based text, Windows' “Unicode”.

The ANSI variant is just a wrapper for the Unicode variant, and it can not logically produce a correct path in all cases.

But this is what you need to use for char based data.

---

An alternative is to use the wide variant of the function, and use whatever machinery that you're comfortable with to convert the wide text result to a byte-oriented char based encoding of your choice, eg UTF-8.

Note that UTF-8 strings can't be used directly to open files etc. via the Windows API, so this approach involves even more conversion just to use the string.

---

However, I recommend switching over to wide text, in Windows.

For this, define the macro symbol UNICODE before including <windows.h> .

That's also the default in a Visual Studio project.

Answer 2

You should use SHGetSpecialFolderPathA() to have the function deal with ANSI characters explicitly.

Then, just convert the array of char to std::string as usual.

/* to have MinGW declare SHGetSpecialFolderPathA() */
#if !defined(_WIN32_IE) || _WIN32_IE < 0x0400
#undef _WIN32_IE
#define _WIN32_IE 0x0400
#endif

#include <shlobj.h>
#include <string>

std::string getPath(int csidl) {
    char out[MAX_PATH];
    if (SHGetSpecialFolderPathA(NULL, out, csidl, 0)) {
        return out;
    } else {
        return "";
    }
}

Answer 3

https://msdn.microsoft.com/en-gb/library/windows/desktop/dd374131%28v=vs.85%29.aspx

#ifdef UNICODE
    typedef wchar_t TCHAR;
#else
    typedef unsigned char TCHAR;
#endif

Basically you can can convert this array to std::wstring . Converting to std::string is straightforward with std::wstring_convert .

http://en.cppreference.com/w/cpp/locale/wstring_convert

Answer 4

Typedef String as either std::string or std::wstring depending on your compilation configuration. The following code might be useful:

#ifndef UNICODE  
  typedef std::string String; 
#else
  typedef std::wstring String; 
#endif