System Calls Used

Table 4-1 summarizes the system calls commonly used in controlling and transferring data and messages within a Stream.

Table 4-1 System Calls Used


Man Page	Description
read(2)	Reads data from a Stream
write(2)	Writes data to a Stream
ioctl(2)	Controls a Stream
getmsg(2)	Receives a message at the Stream head
`getpmsg(2)`	Receives a priority message at the Stream head
putmsg(2)	Sends a message downstream
putpmsg(2)	Sends a priority message downstream
poll(2)	Identifies files on which a user can send or receive messages, or on which certain events have occurred (historically, it was restricted to streams but it does not need to be restricted to streams)
pipe(2)	Creates a bidirectional channel that provides a communication path between multiple processes