Question

I have been trying to implement Win32’s MessageBox using GTK. The app uses SDL/OpenGL, so this isn’t a GTK app.

I handle the initialization (gtk_init) sort of stuff inside the MessageBox function as follows:

int MessageBox(HWND hwnd, const char* text, const char* caption, UINT type) {     GtkWidget *window = NULL;     GtkWidget *dialog = NULL;      gtk_init(&gtkArgc, &gtkArgv);     window = gtk_window_new(GTK_WINDOW_TOPLEVEL);     g_signal_connect(G_OBJECT(window), "delete_event", G_CALLBACK(delete_event), NULL);     g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(destroy), NULL);     // gcallback calls gtk_main_quit()     gtk_init_add((GtkFunction)gcallback, NULL);      if (type & MB_YESNO) {         dialog = gtk_message_dialog_new(GTK_WINDOW(window), GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_QUESTION, GTK_BUTTONS_YES_NO, text);     } else {         dialog = gtk_message_dialog_new(GTK_WINDOW(window), GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_INFO, GTK_BUTTONS_OK, text);     }      gtk_window_set_title(GTK_WINDOW(dialog), caption);     gint result = gtk_dialog_run(GTK_DIALOG(dialog));      gtk_main();      gtk_widget_destroy(dialog);      if (type & MB_YESNO) {         switch (result) {         default:         case GTK_RESPONSE_DELETE_EVENT:         case GTK_RESPONSE_NO:             return IDNO;             break;         case GTK_RESPONSE_YES:             return IDYES;             break;         }     }      return IDOK; }  

Now, I am by no means an experienced GTK programmer, and I realize that I’m probably doing something horribly wrong.

However, my problem is that the last dialog popped up with this function staying around until the process exits. Any ideas?

Answer 1

Hmm, ok. I’d suggest code like this, then:

typedef struct {     int type;     int result; } DialogData;      static gboolean display_dialog(gpointer user_data) {     DialogData *dialog_data = user_data;     GtkWidget *dialog;          if (dialog_data->type & MB_YESNO)         dialog = gtk_message_dialog_new(...);     else         dialog = gtk_message_dialog_new(...);          // Set title, etc.          dialog_data->result = gtk_dialog_run(...);          gtk_main_quit();  // Quits the main loop run in MessageBox()          return FALSE; }      int MessageBox(...) {     DialogData dialog_data;          dialog_data.type = type;          gtk_idle_add(display_dialog, &dialog_data);          gtk_main();          // Do stuff based on dialog_data.result } 

The struct is required because you need to pass around a couple pieces of data. The gtk_idle_add() call adds a method to be run when the main loop is running and idle, and the FALSE return value from the display_dialog() call means that it’s only run once. After we get the result from the dialog, we quit the main loop. That’ll cause the gtk_main() in your main MessageBox() method to return, and you’ll be able to access the result from there.