Variable-length messages.

[Jim Gardner]

>From Waterloo Port comes another way to do it:

#define sendMessage(id,msg)  _sendMessage(id, &(msg), sizeof(msg))
#define receiveMessage(id,msg)	_receiveMessage(id, &(msg), sizeof(msg))

where msg is a struct. If you have a lot of data to pass, you pass a
buffer address and call another routine (Transfer_to or Transfer_from
in Port) to move the data between processes.