C / C++ / MFC

...
// When a server application is launched stand-alone, it is a good idea
//  to update the system registry in case it has been damaged.
if(CUserInfo::isUserPrivilege(DOMAIN_ALIAS_RID_ADMINS))
	m_server.UpdateRegistry(OAT_DISPATCH_OBJECT);
...


// Verify logged in user has a given privelege level
// Returns TRUE upon matching user level
// FALSE upon failure or mismatching user level
//
// Possible Authorities:
// DOMAIN_ALIAS_RID_ADMINS
// DOMAIN_ALIAS_RID_USERS
// DOMAIN_ALIAS_RID_GUESTS
// DOMAIN_ALIAS_RID_POWER_USERS
// DOMAIN_ALIAS_RID_ACCOUNT_OPS
// DOMAIN_ALIAS_RID_SYSTEM_OPS
// DOMAIN_ALIAS_RID_PRINT_OPS
// DOMAIN_ALIAS_RID_BACKUP_OPS
BOOL CUserInfo::isUserPrivilege(DWORD dwSubAuthority)
{
	TOKEN_GROUPS* tgTokens;
	DWORD         group_no;
	PSID          admin_psid;
	HANDLE        hToken, hProcess;
		
	hProcess = GetCurrentProcess();
	ASSERT(hProcess);
	if(hProcess)
	{
		OpenProcessToken(hProcess, TOKEN_QUERY, &hToken);			// get the access token of the current process
		ASSERT(hToken);
		if(hToken)
		{
			GetTokenInformation(hToken, TokenGroups, NULL,0, &group_no);	// passing 0 queries for the group_no
			{
				tgTokens = (TOKEN_GROUPS*)new BYTE[group_no];				// allocate space accordingly
				   
				GetTokenInformation(hToken, TokenGroups, tgTokens, group_no, &group_no);	//get the real info
				{
					SID_IDENTIFIER_AUTHORITY authsid = SECURITY_NT_AUTHORITY;	// we'll look for admin priveleges
					
					if(AllocateAndInitializeSid(&authsid, 2, SECURITY_BUILTIN_DOMAIN_RID,
						dwSubAuthority,0,0,0,0,0,0, &admin_psid))
					{
				
						for (int i = 0; i < tgTokens->GroupCount; i++)
							if (EqualSid(tgTokens->Groups[i].Sid, admin_psid))		// does this identify an admin?
							{
								delete [] tgTokens;
								CloseHandle(hToken);
								FreeSid(admin_psid);
								return TRUE;			// Match
							}
								
						return FALSE;				// No match
					}
				}
			}
		}
	}

	return FALSE;		// Failure opening process / token
}

(CMainFrame*)(AfxGetMainWnd())->GetActiveDocument();

CMainFrame * pWnd =dynamic_cast<CMainFrame *>(AfxGetApp()->m_pMainWnd);
ASSERT_VALID(pWnd);

CMyDoc * pDoc =dynamic_cast<CMyDoc *>(pWnd->GetActiveDocument());
ASSERT_VALID(pDoc);