使用WinAPI获取C中当前用户的桌面路径

Question

I'm very new to WinAPI programming. I was wondering how I could get the path of the user's Desktop and then print out the full path to the console. This is my current code:

TCHAR* path = 0;
HRESULT result = SHGetKnownFolderPath(&FOLDERID_Desktop, 0, NULL, &path);
if (result == S_OK)
{
    printf("%s\n", path);
}
CoTaskMemFree(path)

It does find the path, but it prints out "C" for the path rather than the entire path with slashes. What am I missing?

Thanks!

Answer 1

SHGetKnownFolderPath() outputs a wchar_t* pointer, not a TCHAR* pointer. There is no ANSI version of SHGetKnownFolderPath() , so you should not be using TCHAR at all in this situation. In fact, your code will not compile unless UNICODE is defined so TCHAR maps to wchar_t .

The reason you only see the 1st character is because you are passing a wchar_t* where a char* is expected. On Windows, wchar_t is 16-bit, and so wchar_t* strings are encoded in UCS-2 or UTF-16LE. All ASCII characters in UCS-2/UTF-16LE have their high 8 bits set to 0. Your use of printf() is expecting a null terminated char* string, so the high 0x00 byte of the 1st wchar_t character gets misinterpreted as a null terminator.

To do what you want, you need to print out the returned path as-is as a wide string, not as a (misinterpreted) narrow string.

You could use %S with printf() , eg:

PWSTR path;
if (SHGetKnownFolderPath(&FOLDERID_Desktop, 0, NULL, &path) == S_OK)
{
    printf("%S\n", path);
    CoTaskMemFree(path);
}

But this is not portable across compilers. You should use %s with wprintf() instead:

PWSTR path;
if (SHGetKnownFolderPath(&FOLDERID_Desktop, 0, NULL, &path) == S_OK)
{
    wprintf(L"%s\n", path);
    CoTaskMemFree(path);
}

Answer 2

It prints a single character because you tried to print a wide string as a narrow string. You probably have UNICODE/_UNICODE defined so TCHAR is WCHAR.

If you insist on using TCHAR you should use the correct printing function from tchar.h:

_tprintf(_T("%s\n"), path);

Otherwise you can use the wide version:

wprintf(L"%s\n", path);

Or the worst solution, convert the string to a narrow codepage string:

printf("%ls\n", path); // This might not display all Unicode characters correctly