Exchange/SNA Manual

4 Using the Exchange/SNA
Programmatic Interface
104700 Tandem Computers Incorporated 4–1
This section provides instruction on how to use the Exchange/SNA programmatic
interface to send files to and receive files from a host system. This section covers the
following information:
A summary of the system procedure calls used with Exchange/SNA
Programming considerations
Step-by-step instructions for using the programmatic interface
Information about using Exchange/SNA with existing programs
System Procedure Call
Summary
The programmatic interface lets your program control and communicate with the
Exchange/SNA line server through standard system procedure calls. Table 4-1 lists
the system procedure calls most frequently used to control and communicate with the
line server and briefly describes the function of each. For a detailed description of
these system procedure calls and how they are used with the Exchange/SNA line
server, see Section 5. For the complete definition of all system procedure calls, see the
Guardian Procedure Calls Reference Manual.
Table 4-1. System Procedure Call Summary
Procedure Function
AWAITIO Completes (or checks for completion of) a previously initiated nowait I/O operation.
CLOSE Terminates access to a previously opened subdevice supported by the
Exchange/SNA line server.
CONTROL Sends an end-of-file message to the host, sends an abort message to the host, or
terminates the sessions with the host and stops the line server.
OPEN Establishes communication between your program and a subdevice supported by
the Exchange/SNA line server.
READ Reads a record sent by the host to the specified subdevice.
SETMODE Sets the parameters for send and receive operations.
WRITE Writes a record from your program to the specified subdevice for transmission to the
host.
WRITEREAD Performs the same function as WRITE or READ.