Get Document Directory - c++

Question

I'm working on a little singleplayer cheat for a game and am planning on making it public, I have written the API and it all works well but I want to save the data that the user enters to a .ini file so that they will only have to log in one time unless their credentials change. I have done this and it works with a relative path C:\Users\Name\Documents\Cheat\Authorise.ini Although When check the result, it doesn't seem to save nor read the data in the file.
I'm wondering if there is a better way to get the Documents Directory.
Function:
std::string authFile = "C:\\Users\\%USERNAME%\\Documents\\Cheats\\Authorise.ini";
std::string username = GUI::Files::ReadStringFromIni(authFile, "Login", "Username");
std::string password = GUI::Files::ReadStringFromIni(authFile, "Login", "Password");`

Answer 1

Since you're on Windows, you should use the Windows API call available for this very purpose in <ShlObj.h> called SHGetKnownFolderPath. Note that you had best use a std::wstring instead for this purpose, since there is no variant of SHGetKnownFolderPath that accepts an MBCS or ANSI string. Also, this will get you the entire path to the user's profile directory, not just the username.
PWSTR path;
SHGetKnownFolderPath(FOLDERID_Documents, KF_FLAG_DEFAULT, NULL, &path);
std::wstring strpath(path);
CoTaskMemFree(path);
Also, once you're done with path, free it with CoTaskMemFree.

Answer 2

Different versions of Windows store user profiles in different locations, and even the default name of the Documents folder can differ. In fact, the name and location of the user's Documents folder is fully customizable by the user, and may not even be located under the user's profile at all. So, you should not assume the Documents folder is always located at C:\\Users\\%USERNAME%\\Documents.
The best way to get the correct path to a user's Documents folder on all versions of Windows is to simply ask Windows itself. Use SHGetFolderPath(CSIDL_MYDOCUMENTS) (pre-Vista) or SHGetKnownFolderPath(FOLDERID_Documents) (Vista+) for that, eg:
#include <shlobj.h>
#include <shlwapi.h>
std::string GetDocumentsFolder()
{
std::string path;
char szPath[MAX_PATH+1] = {};
if (SHGetFolderPathA(NULL, CSIDL_MYDOCUMENTS, NULL, SHGFP_TYPE_CURRENT, szPath) == S_OK)
path = PathAddBackslashA(szPath);
/*
PWSTR pPath = NULL;
if (SHGetKnownFolderPath(FOLDERID_Documents, KF_FLAG_DEFAULT, NULL, &pPath) == S_OK)
{
int wlen = lstrlenW(pPath);
int len = WideCharToMultiByte(CP_ACP, 0, pPath, wlen, NULL, 0, NULL, NULL);
if (len > 0)
{
path.resize(len+1);
WideCharToMultiByte(CP_ACP, 0, pPath, wlen, &path[0], len, NULL, NULL);
path[len] = '\\';
}
CoTaskMemFree(pPath);
}
*/
return path;
}
std::string GetAuthFilePath()
{
std::string path = GetDocumentsFolder();
if (!path.empty())
path += "Cheats\\Authorise.ini";
return path;
}
std::string authFile = GetAuthFilePath();
...