DWORD GetLongPathName(
LPCTSTR lpszShortPath, // file name
LPTSTR lpszLongPath, // path buffer
DWORD cchBuffer // size of path buffer
);
Return Values
If the function succeeds, the return value is the length of the string copied to the lpszLongPath parameter, in TCHARs. This length does not include the terminating null character.
If lpszLongPath is too small, the function returns the size, in TCHARs, of the buffer required to hold the long path.
If the function fails, the return value is zero. To get extended error information, call GetLastError.