Modifies a pointer to a #GstMessage to point to a different #GstMessage. The
modification is done atomically (so this is useful for ensuring thread safety
in some cases), and the reference counts are updated appropriately (the old
message is unreffed, the new one is reffed).
Either @new_message or the #GstMessage pointed to by @old_message may be %NULL.
Modifies a pointer to a #GstMessage to point to a different #GstMessage. The modification is done atomically (so this is useful for ensuring thread safety in some cases), and the reference counts are updated appropriately (the old message is unreffed, the new one is reffed).
Either @new_message or the #GstMessage pointed to by @old_message may be %NULL.