Specifications

Interfaces Page 16
Success - a port was opened.
No resources
- the data link does not have sufficient
resources to open a port.
Unrecognized channel
- there is no channel with the specified
identification.
Channel in wrong state
- the channel is not in a state where a
port canbe opened.
Port-id
- a port identification to be used in the other data link
interface functions.
3.1.3 Close
Function:
Closes an open port and releases all its resources.
A port cannot
be closed unless all outstanding transmit or receive requests are
completed.
Inputs:
Port-id
- a port identification assigned by the Open function.
Outputs:
Return-code
- the status of the request. One of:
Success
- the port is closed.
Unrecognized port
- there is no open port with the specified
identification.
Calls outstanding
- there are uncompleted transmit or receive
requests outstanding on the port.
3.1.4 Transmit
Funct ion:
Queues a frame to
be transmitted. The user tests for completion
by using Transmit-poll. Transmission of a frame always succeeds
or fails within such a small amount of time that an abort function
is not necessary.
Inputs:
Por't-id
- a port identification assigned by the Open function.