Printing value of entry box in a dialog in gtk c - c

Question

I have worked recently with gtk+ in c language.
I have tried to communicate between two callbacks in a dialog and not in the main window (like here). But, unlike the solutions in the link, the program crushes (in the second callback when I try to use the widget I get from the parameters).
This is my code for This:
#include <gtk/gtk.h>
#include <stdlib.h>
#include <stdio.h>
static void print_text (GtkWidget *widget, gpointer data)
{
GtkEntry* entry = data;
printf("%s", gtk_entry_get_text(entry));
}
static void open_dialog (GtkWidget *widget, gpointer data)
{
GtkWidget *window = data;
GtkWidget *dialog;
GtkWidget *content_area;
GtkWidget *grid;
GtkWidget *label;
GtkWidget *button;
static GtkEntry *textbox;
dialog = gtk_dialog_new_with_buttons ("Get Text",
window,
GTK_DIALOG_MODAL,
GTK_STOCK_OK,
GTK_RESPONSE_OK,
NULL);
content_area = gtk_dialog_get_content_area (GTK_DIALOG (dialog));
grid = gtk_grid_new();
gtk_container_add (GTK_CONTAINER (content_area), grid);
label = gtk_label_new("Value: ");
gtk_grid_attach(GTK_GRID(grid), label, 0, 0, 1, 1);
textbox = gtk_entry_new();
gtk_entry_set_text(textbox, "<Value>");
gtk_grid_attach(GTK_GRID(grid), textbox, 1, 0, 1, 1);
gtk_widget_show_all (dialog);
g_signal_connect (GTK_DIALOG (dialog), "response", G_CALLBACK (print_text), textbox);
}
static void activate (GtkApplication *app, gpointer user_data)
{
GtkWidget *window;
GtkWidget *button;
GtkWidget *entry;
GtkWidget *grid;
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "Window");
gtk_container_set_border_width (GTK_CONTAINER (window), 10);
grid = gtk_grid_new ();
gtk_container_add (GTK_CONTAINER (window), grid);
button = gtk_button_new_with_label ("Print Text");
g_signal_connect (button, "clicked", G_CALLBACK (open_dialog), window);
gtk_grid_attach (GTK_GRID (grid), button, 0, 1, 1, 1);
gtk_widget_show_all (window);
}
int main (int argc, char **argv)
{
GtkApplication *app;
int status;
app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
The program should have printed the value of the entry box which in the dialog after closing the dialog. Note: in the main window there is a button that opens the dialog.
Thanks for helping!

Answer 1

Problem is on the print_text function. The prototype for GtkDialog response signal is:
void user_function (GtkDialog *dialog,
gint response_id,
gpointer user_data)
So you must change your function to:
static void print_text (GtkWidget *widget, gint response_id, gpointer data)
{
GtkEntry* entry = data;
printf("%s", gtk_entry_get_text(entry));
gtk_widget_destroy (widget); // This will close the dialog
}