#include <gdk/gdk.h>
/*

gdk_pixmap_new (drawable, width, height, depth) :
 g_return_val_if_fail (drawable == NULL || GDK_IS_DRAWABLE (drawable), NULL);
 g_return_val_if_fail ((drawable != NULL) || (depth != -1), NULL);
 g_return_val_if_fail ((width != 0) && (height != 0), NULL);

resultat :

$ gcc `pkg-config --libs --cflags gdk-2.0` t.c -o t
$ ./t

(process:25289): Gdk-CRITICAL **: gdk_pixmap_new: assertion `(drawable != NULL) || (depth != -1)' failed
0
*/

int main() {
        GdkPixmap*  pixmap;
        pixmap = gdk_pixmap_new (NULL, 0, 0, -1);
        printf("%x\n", pixmap);
        return 0;
}