C++ Games: registry

The example in this topic uses the RegOpenKeyEx, RegEnumKeyEx, and RegDeleteKey functions to delete a registry key with subkeys.

To test this example, create the following registry key by using Regedt32.exe, and then add a few values and subkeys:

HKEY_CURRENT_USER\Software\TestDir

After running the code, use the F5 key to refresh the registry data, and notice that the TestDir key is deleted.

____________________________________________________________________

#include <windows.h>
#include <stdio.h>
#include <strsafe.h>
//*************************************************************
//
//  RegDelnodeRecurse()
//
//  Purpose:    Deletes a registry key and all it's subkeys / values.
//
//  Parameters: hKeyRoot    -   Root key
//              lpSubKey    -   SubKey to delete
//
//  Return:     TRUE if successful.
//              FALSE if an error occurs.
//
//*************************************************************

BOOL RegDelnodeRecurse (HKEY hKeyRoot, LPTSTR lpSubKey)
{
    LPTSTR lpEnd;
    LONG lResult;
    DWORD dwSize;
    TCHAR szName[MAX_PATH];
    HKEY hKey;
    FILETIME ftWrite;

    // First, see if we can delete the key without having
    // to recurse.

    lResult = RegDeleteKey(hKeyRoot, lpSubKey);

    if (lResult == ERROR_SUCCESS) 
        return TRUE;

    lResult = RegOpenKeyEx (hKeyRoot, lpSubKey, 0, KEY_READ, &hKey);

    if (lResult != ERROR_SUCCESS) 
    {
        if (lResult == ERROR_FILE_NOT_FOUND) {
            printf("Key not found.\n");
            return TRUE;
        } 
        else {
            printf("Error opening key.\n");
            return FALSE;
        }
    }

    // Check for an ending slash and add one if it is missing.

    lpEnd = lpSubKey + lstrlen(lpSubKey);

    if (*(lpEnd - 1) != TEXT('\\')) 
    {
        *lpEnd =  TEXT('\\');
        lpEnd++;
        *lpEnd =  TEXT('\0');
    }

    // Enumerate the keys

    dwSize = MAX_PATH;
    lResult = RegEnumKeyEx(hKey, 0, szName, &dwSize, NULL,
                           NULL, NULL, &ftWrite);

    if (lResult == ERROR_SUCCESS) 
    {
        do {

            StringCchCopy (lpEnd, MAX_PATH*2, szName);

            if (!RegDelnodeRecurse(hKeyRoot, lpSubKey)) {
                break;
            }

            dwSize = MAX_PATH;

            lResult = RegEnumKeyEx(hKey, 0, szName, &dwSize, NULL,
                                   NULL, NULL, &ftWrite);

        } while (lResult == ERROR_SUCCESS);
    }

    lpEnd--;
    *lpEnd = TEXT('\0');

    RegCloseKey (hKey);

    // Try again to delete the key.

    lResult = RegDeleteKey(hKeyRoot, lpSubKey);

    if (lResult == ERROR_SUCCESS) 
        return TRUE;

    return FALSE;
}

//*************************************************************
//
//  RegDelnode()
//
//  Purpose:    Deletes a registry key and all it's subkeys / values.
//
//  Parameters: hKeyRoot    -   Root key
//              lpSubKey    -   SubKey to delete
//
//  Return:     TRUE if successful.
//              FALSE if an error occurs.
//
//*************************************************************

BOOL RegDelnode (HKEY hKeyRoot, LPTSTR lpSubKey)
{
    TCHAR szDelKey[2 * MAX_PATH];

    StringCchCopy (szDelKey, MAX_PATH*2, lpSubKey);
    return RegDelnodeRecurse(hKeyRoot, szDelKey);

}

void main()
{
   BOOL bSuccess;

   bSuccess = RegDelnode(HKEY_CURRENT_USER,
      TEXT("Software\\TestDir"));

   if(bSuccess)
      printf("Success!\n");
   else printf("Failure.\n");
}