gtk set label text:assertion ' gtk is label

bonsoir!!
je uis débutant en gtk et comme indique le titre quand j'éxecute mon programme la label ne subit aucune changement et cette phrase s'affiche en cmd "gtk set label text:assertion ' gtk is label"
voici le code et merci d'avance

Code:

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#include <stdio.h>
#include <stdlib.h>
#include <gtk/gtk.h>
 
typedef struct s_win
{
    GtkWidget * win;
    GtkWidget * pt;
    GtkWidget * pl;
    GtkWidget * pb;
}t_win;
void static  cb_exit(GtkWidget *button, gpointer data) {
   t_win *fen=(t_win*) data;
   gtk_label_set_text(GTK_LABEL(fen->pl),"chito");
 
}
int main (int argc,char** argv)
{
    gtk_init(&argc,&argv);
    t_win *inter=(t_win*)malloc(sizeof(t_win));
    inter->win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size(GTK_WINDOW(inter->win), 500, 300);
    gtk_window_set_position(GTK_WINDOW(inter->win), GTK_WIN_POS_CENTER);
     inter->pt =gtk_table_new(15, 20, TRUE);
inter->pl=gtk_label_new("test");
gtk_table_attach_defaults(inter->pt, inter->pl,5, 10, 10, 11);
 
inter->pb = gtk_button_new_with_mnemonic("Cliquer ici pour _Quitter");
//gtk_button_set_relief(inter->pb, GTK_RELIEF_HALF);
gtk_table_attach_defaults(inter->pt, inter->pb,5, 10, 12, 13);
gtk_container_add(GTK_CONTAINER(inter->win),inter->pt);
g_signal_connect(inter->pb, "clicked",(GCallback)cb_exit, NULL);
 
 
    gtk_window_set_title(GTK_WINDOW(inter->win),"besmelleh");
    gtk_widget_show_all(inter->win);
    gtk_main();
    return EXIT_SUCCESS;
}