GTK3 : gtk_widget_destroy versus gtk_widget_hide - c

Question

Here a short MCV to illustrate the problem I meet :
I call a dialog box from my main window.
I click on one of the buttons from the dialog (usual way I think)
If I click again on one button, dialog will not display again (I got a bunch of errors instead).
This doesn't happen of I use gtk_widget_hide instead.
(interfaces are designed with Glade3)
typedef struct {
GtkBuilder *builder;
gchar *stuff;
} Context;
void conDisplay(GtkWidget *g, gpointer userdata) {
GtkWidget *dlg, *parent;
Context *ctx=(Context *)userdata;
int ret=0;
g_printerr("clicked\n");
parent=GTK_WIDGET(gtk_builder_get_object(ctx->builder,(gchar *)"MCV"));
if (ctx->stuff) {
g_printerr("Already connected\n");
dlg=GTK_WIDGET(gtk_builder_get_object(ctx->builder,(gchar *)"question"));
gtk_window_set_transient_for(GTK_WINDOW(dlg),GTK_WINDOW(parent));
ret=gtk_dialog_run(dlg);
if (ret==-3) { // OK clicked
g_printerr("OK from Already connected\n");
}
else { g_printerr("Unknown\n"); }
gtk_window_set_transient_for(GTK_WINDOW(dlg),NULL);
gtk_widget_destroy(GTK_WIDGET(dlg));
} else {
dlg=GTK_WIDGET(gtk_builder_get_object(ctx->builder,(gchar *)"connect"));
gtk_window_set_transient_for(GTK_WINDOW(dlg),GTK_WINDOW(parent));
ret=gtk_dialog_run(dlg);
if (ret==-1) { // GO clicked
g_printerr("GO\n");
ctx->stuff="Hello";
}
else { g_printerr("Cancel\n"); }
gtk_window_set_transient_for(GTK_WINDOW(dlg),NULL);
gtk_widget_destroy(GTK_WIDGET(dlg));
}
}
int main(int argc, char **argv)
{
Context ctx;
GtkWidget *mainwin;
GtkWidget *btnCon;
GError *error=NULL;
/* Init GTK+ */
gtk_init(&argc,&argv);
ctx.builder=gtk_builder_new();
ctx.stuff=NULL;
// Load UI from file.
gtk_builder_add_from_file(ctx.builder,"mcv.glade",&error);
mainwin=GTK_WIDGET(gtk_builder_get_object(ctx.builder,(gchar *)"MCV"));
btnCon=GTK_WIDGET(gtk_builder_get_object(ctx.builder,(gchar *)"con"));
g_signal_connect(btnCon, "clicked", (GCallback)conDisplay, &ctx);
gtk_widget_show_all(mainwin);
gtk_main();
return 0;
}
Thanks for your help !
Best regards.
V.

Answer 1

From GtkBuilder:
A GtkBuilder holds a reference to all objects that it has constructed and drops these references when it is finalized. This finalization can cause the destruction of non-widget objects or widgets which are not contained in a toplevel window. For toplevel windows constructed by a builder, it is the responsibility of the user to call gtk_widget_destroy() to get rid of them and all the widgets they contain.
Since GtkDialog inherits from GtkWindow I would suggest separating mainwin and dlg GtkBuilders and gladefiles and use temporary GtkBuilder in conDisplay:
void conDisplay(GtkWidget *g, gpointer userdata) {
GtkWidget *dlg, *parent;
Context *ctx=(Context *)userdata;
GtkBuilder *builder = gtk_builder_new_from_file("dlg.glade"); //or even pass glade filename in Context
/* rest of the code */
gtk_widget_destroy(GTK_WIDGET(dlg));
g_object_unref(G_OBJECT(builder));
}