pixmap doesn´t show in drawing_area

[der gilb tripmywire de]

Hello,

I´d like my programm to open a window and draw some boxes (or what ever)
into it. I came to the conclusion that a drawing_area and a pixmap
should do this.
So I created a drawing_area and a pixmap. Then I tried to draw someting
onto the pixmap and put it on the drawing_area. But nothing was
displayed in the window.
Perhaps I did some mistakes with the draw methods, I thought, so I tried
to show an xpm.
But only the window with the empty drawing_area and some errors/
warnings 
(
  Gdk-WARNING **: Creating pixmap from xpm with NULL window and colormap
  Gdk-CRITICAL **: file gdkdraw.c: line 379 (gdk_draw_pixmap): assertion
'drawable != NULL' failed. 
) appeared.

I think
	pixmap = gdk_pixmap_create_from_xpm(drawing_area->window,0,0,
"vnterm.xpm");
causes the trouble. If I write NULL instead of 0, my compiler tells me:
ANSI C++ forbids implicit conversion from 'void *' in argument passing.

I use gcc 2.95.3 and GTK 1.2.9

The Tutorial/ FAQ and the few help I found in the net couldn´t help me.
I attached my code and hope somebody can and is willing to help me.

Thank you,

dennis

<code>
#include <gtk/gtk.h>
#include <gdk/gdk.h>

int main (int argc, char *argv[])
{
	gint window_delete_event(void);
	void exit_prog( GtkWidget *,gpointer data);

	GtkWidget *main_window;
	GtkWidget *drawing_area;
	GdkGC *gc;
	GdkPixmap *pixmap;

	gtk_init(&argc, &argv);

	main_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
	drawing_area = gtk_drawing_area_new();

	gtk_container_add (GTK_CONTAINER(main_window), drawing_area);

	gtk_signal_connect (	GTK_OBJECT (main_window),
				"delete_event",
				GTK_SIGNAL_FUNC (window_delete_event),
				NULL);

	gtk_signal_connect (	GTK_OBJECT(main_window),
				"destroy",
				GTK_SIGNAL_FUNC(exit_prog),
				NULL);

	pixmap = gdk_pixmap_create_from_xpm(drawing_area->window,0,0,
"vnterm.xpm");
	gc = drawing_area->style->fg_gc[GTK_WIDGET_STATE(drawing_area)];

	gdk_draw_pixmap(drawing_area->window,
			gc,
			pixmap,
			0,0,0,0,300,300);

	gtk_widget_show(drawing_area);
	gtk_widget_show(main_window);

	gtk_main();

	return(0);
}

gint window_delete_event(void)
{
	return(FALSE);
}

void exit_prog( GtkWidget *,
		gpointer data)
{
	gtk_main_quit();
}
</code>