Should I use a global variable in gtk callback functions? [duplicate] - c

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Passing additional arguments to gtk function
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GTK passing structure to callback function in C
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Hi I'm trying to program with GTK+ 2 and when I need to create a popup window after the "clicked' signal of a button, I use " gtk_widget_set_sensitive(button, FALSE) " so as not to be able to launch another popoup window from the same button when one is already launched. Yet the only way to close the popup with another callback function containing " gtk_widget_destroy(popup) " also means this callback can't "see" the first button to turn it sensitive again. Should I use a global variable and asign the popup window to it so my second callback function will see it? Or do I define more global widgets ?
What I'm really getting at is using global variables in something like GTK a common thing to do?, such as in header files, or is it bad practice at all?
Here is a sample program (with less stuff in the first callback than normal!)
#include <gtk/gtk.h>
// Is it good to set a temporary global GtkWidget * so I can asign it to
// button1 later and then use this temporary variable to set the widget sensitive again.
// GtkWidget * temp;
static void popup_win(GtkWidget *, gpointer data);
static void close_up(GtkWidget *, GtkWidget *);
int main(int argc, char * argv[])
{
GtkWidget * window, * button1, * vbox;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "EXAMPLE PROGRAM");
gtk_container_set_border_width(GTK_CONTAINER(window), 10);
gtk_widget_set_size_request(window, 800, 300);
button1 = gtk_button_new_with_label("Click here");
g_signal_connect(G_OBJECT(button1), "clicked",
G_CALLBACK(popup_win), NULL);
vbox = gtk_vbox_new(FALSE, 0);
gtk_box_pack_start(GTK_BOX(vbox), button1, FALSE, FALSE, 0);
gtk_container_add(GTK_CONTAINER(window), vbox);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
static void popup_win(GtkWidget * btn, gpointer data)
{
gtk_widget_set_sensitive(btn, FALSE);
// I could use temp here. Then get to it in close_up function.
// temp = btn
GtkWidget * window2, * button2, * hbox;
window2 = gtk_window_new(GTK_WINDOW_POPUP);
gtk_window_set_title(GTK_WINDOW(window2), "POPUP WINDOW");
gtk_container_set_border_width(GTK_CONTAINER(window2), 10);
gtk_widget_set_size_request(window2, 100, 200);
button2 = gtk_button_new_with_label("Click me too");
g_signal_connect(G_OBJECT(button2), "clicked",
G_CALLBACK(close_up), (gpointer) window2);
hbox = gtk_hbox_new(TRUE, 0);
gtk_box_pack_start(GTK_BOX(hbox), button2, FALSE, FALSE, 0);
gtk_container_add(GTK_CONTAINER(window2), hbox);
gtk_widget_show_all(window2);
}
static void close_up(GtkWidget * btn, GtkWidget * win)
{
// can't get at button1 so I can't set widget sensitve again.
// gtk_widget_set_sensitive(button1, TRUE);
// Unless I'm using temp variable.
// gtk_widget_set_sensitive(temp, TRUE);
gtk_widget_destroy(win);
}```