delete a logical instance
int delloins(ptfig, insname)
Pointer to the figure in which the instance should be deleted
Name of the instance to be deleted.
delloins delete the instance called insname in the figure
pointed to by ptfig. This instance is warrantied to be unique, because
its name is an identifier at the given hierarchical level.
The list consistency is maintainded, and the space freed. The instance
connectors are also freed, since if the instance disapear, no more connections
can occur on it.
delloins returns 1 if the instance has been deleted, 0
if no such instance exists in the list.
char *was_existing(ptfig, insname)
return delloins(ptfig, insname) ? "you just killed it!"
: "wasn't here anyway";