Understanding NT

Listing 3: main.c — Demo program source

// main.c

#define UNICODE
#define _UNICODE

#include <windows.h>
#include "main.h"
#include "symlink.h"

BOOL CALLBACK MainDlgProc(HWND, UINT, WPARAM, LPARAM);
VOID Init(LPTSTR, LPTSTR, DWORD, DWORD);
BOOL Refresh(HWND);

HINSTANCE hInst;
HKEY      ghLinkKey;

//-----------------------------------------------------------------
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInst,
                     LPSTR lpCmdLine, int nCmdShow)
{
    hInst = hInstance;

    // Create some dummy keys to test symbolic links

    Init(TEXT("Software\\PaulaT\\A"), TEXT("AAA"), 8, 1);
    Init(TEXT("Software\\PaulaT\\B"), TEXT("BBB"), 8, 2);
    Init(TEXT("Software\\PaulaT\\C"), TEXT("CCC"), 8, 3);

    return DialogBox(hInst, MAKEINTRESOURCE(SYMLINK_DLG), 
                     NULL, MainDlgProc);
} // WinMain

//-----------------------------------------------------------------
void Init(LPTSTR szKey, LPTSTR sz, DWORD size, DWORD dw)
{
    HKEY hKey;
    DWORD status;

    status = RegCreateKeyEx(HKEY_LOCAL_MACHINE, szKey, 0, NULL, 
                            REG_OPTION_NON_VOLATILE, 
                            KEY_ALL_ACCESS, 0, &hKey, 0);
    if (status == ERROR_SUCCESS) {
        RegSetValueEx(hKey,TEXT("Val1"),0,REG_SZ,(LPBYTE)sz,size);
        RegSetValueEx(hKey,TEXT("Val2"),0,REG_DWORD,(LPBYTE)&dw,4);
        RegCloseKey(hKey);
    }
} // Init

//-----------------------------------------------------------------
int CALLBACK MainDlgProc(HWND hDlg, UINT Message,WPARAM wParam,
                         LPARAM lParam)
{
    DWORD status;

    switch (Message) {
        case WM_INITDIALOG:
            status = CreateSymLinkKey(HKEY_LOCAL_MACHINE,
                                      TEXT("Software\\PaulaT"),
                                      TEXT("Current"), &ghLinkKey);
            if (status != ERROR_SUCCESS) {
                EnableWindow(GetDlgItem(hDlg, ID_MODE_A), FALSE);
                EnableWindow(GetDlgItem(hDlg, ID_MODE_B), FALSE);
                EnableWindow(GetDlgItem(hDlg, ID_MODE_C), FALSE);
                Refresh(hDlg);
            }
            return TRUE;

        case WM_COMMAND:
            switch (LOWORD(wParam)) {
                case ID_MODE_A:
                    SetSymLink(ghLinkKey, HKEY_LOCAL_MACHINE,
                               TEXT("Software\\PaulaT\\A"));
                    Refresh(hDlg);
                    break;

                case ID_MODE_B:
                    SetSymLink(ghLinkKey, HKEY_LOCAL_MACHINE,
                               TEXT("Software\\PaulaT\\B"));
                    Refresh(hDlg);
                    break;
                case ID_MODE_C:
                    SetSymLink(ghLinkKey, HKEY_LOCAL_MACHINE,
                               TEXT("Software\\PaulaT\\C"));
                    Refresh(hDlg);
                    break;
            }
            break;
        

        case WM_CLOSE:
            EndDialog(hDlg, 1);
            break;

        default:
            return FALSE;
    }
    return FALSE;

} // MainDlgProc

//-----------------------------------------------------------------
BOOL Refresh(HWND hDlg)
{
    HKEY hKey = NULL;
    DWORD status, t, s, dw2 = 0;
    TCHAR sz1[MAX_PATH];

    status = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
                          TEXT("Software\\PaulaT\\Current"), 0, 
                          KEY_READ, &hKey);

    if (status == ERROR_SUCCESS) {
        s = MAX_PATH * sizeof(TCHAR);
        RegQueryValueEx(hKey,TEXT("Val1"),0,&t,(LPBYTE)sz1,&s);
        SetDlgItemText(hDlg,ID_VAL_1,sz1);

        s = sizeof(DWORD);
        RegQueryValueEx(hKey,TEXT("Val2"),0,&t,(LPBYTE)&dw2,&s);
        SetDlgItemInt(hDlg,ID_VAL_2,dw2,FALSE);

        RegCloseKey(hKey);
        return TRUE;
    }
    return FALSE;

} // Refresh
//End of File