NAME
        ActivateCxObj -- change the activation state of a commodity object.
                         (V36)

   SYNOPSIS
        previous = ActivateCxObj(co,true);
        D0                       A0 D0

        long activatecxobj(cxobj *,long);

   FUNCTION
        Commodity objects of all types maintain an activation state.
        If an object is "active", then it performs its particular action
        whenever a commodity message arrives. If the object is "inactive"
        no action is taken, and the message goes on to its next destination.

        All objects are created in the "active" state except brokers
        which are created "inactive". Thus, after you create your
        broker and hang a tree of objects off of it, you must remember
        to use this function to activate it. This causes it to divert all
        messages to your tree of objects.

        This function activates 'co' if 'true' is different than 0. and
        deactivates it otherwise. The previous activation state is
        returned.

   INPUTS
        co - the commodity object to affect (may be NULL)
        true - 0 to deactivate the object, anything else to activate it

   RESULTS
        previous - the previous activation state: 0 if the object was
                   inactive or if 'co' was NULL, anything else if the object
                   was active

   SEE ALSO
        cxbroker()