Mine

void gdso_textview_print_message(GtkTextView *textview, char *message)
{
    /*GtkTextBuffer *buffer;
    GtkTextIter end;
    
    buffer = gtk_text_view_get_buffer(textview);
    gtk_text_buffer_get_end_iter(buffer, &end);
    gtk_text_buffer_insert(buffer, &end, message, -1);*/
}

static void on_start_clicked(GtkButton *button, gpointer data)
{
    GdsoState *tmp_data = (GdsoState *) data;

    if(tmp_data->stopped == 0)
    {
	tmp_data->stopped = 1;
        GtkButton *button = GTK_BUTTON(tmp_data->start);
	gtk_button_set_label(button, "STOP");

	const char *size = gtk_entry_get_text(GTK_ENTRY(tmp_data->entry1));
	char *tmp_size = malloc(sizeof(char) * strlen(size) + 1);
	sprintf(tmp_size, "%s", size);

        tmp_data->size = tmp_size;

	char *args[2];
	args[1] = tmp_data->path;
	args[2] = tmp_data->size;

	int exit_status = run(tmp_data, args);

	if(exit_status == 0)
---->       gdso_textview_print_message(GTK_TEXT_VIEW(tmp_data->textview1), "TASK COMPLETED!\n\n");
	else
            gdso_textview_print_message(GTK_TEXT_VIEW(tmp_data->textview1), "TASK HALTED!\n\n");
    }
    else
    {
        tmp_data->stopped = 0;
	GtkButton *button = GTK_BUTTON(tmp_data->start);
	gtk_button_set_label(button, "START");
    }
}