Cause a pixmap to join a group.
#include <screen/screen.h>
int screen_join_pixmap_group(screen_pixmap_t pix, const char *name)
The handle of the pixmap that is to be joining the group.
A unique string that identifies the group.
0 if the request for the pixmap to join the group was queued for processing, or -1 if an error occurred (errno is set).