C++ Problem not return network drive (Z:/) , with running the program in RunAsAdmin mode

Question

I have written a program to display the available drives.

I want this program to work on all versions of Windows.

I have a problem, when I run the program with RunAsAdministrator, it does not display the sharing drive. How can I solve this problem?

#include <windows.h>
#include <direct.h>
#include <stdio.h>
#include <tchar.h>
TCHAR g_szDrvMsg[] = _T("A:\n"); //what does g_szDrvMsg do and what is TCHAR type?
int main(int argc, char* argv[]) {
    ULONG uDriveMask = _getdrives(); //what is ULONG equivalent of C++ or it is just ULONG?
    if (uDriveMask == 0)
    {
        printf("_getdrives() failed with failure code: %d\n",
            GetLastError()); //So GetLastError retuns a sring or char*?
    }
    else
    {
        printf("The following logical drives are being used:\n");

        while (uDriveMask) {
            if (uDriveMask & 1)
                printf(g_szDrvMsg);

            ++g_szDrvMsg[0];
            uDriveMask >>= 1;
        }
    }
    getchar();
}