Exchange/SNA Manual

CONTROL Procedure
Exchange/SNA System Procedure Calls
104700 Tandem Computers Incorporated 5–9
CONTROL Procedure The CONTROL procedure sends an end-of-file message, an abort transmission
message, or terminates the sessions with the host and stops the line server.
CALL CONTROL ( filenum
, operation
,
, [ tag ] );
filenum
INT:value
is the file number of a previously opened subdevice supported by the
Exchange/SNA line server. The number you specify here is the number returned
by the call to OPEN that opened the subdevice.
operation
INT:value
specifies the operation to perform. The allowed values of operation are:
2 Sends an end-of-file message to the host.
13 Sends an abort transmission message to the host.
19 Terminates the sessions with the host and stops the line server.
tag
INT(32):value
identifies individual nowait I/O operations when a single file can have two or
more nowait I/O operations outstanding at the same time. The value of tag is a
unique, arbitrary value that your program defines for each nowait I/O operation.
A subsequent call to AWAITIO that completes this I/O operation returns this
value to your program, identifying this I/O operation as the nowait I/O operation
that just completed.
If your program has no more than one outstanding nowait I/O operation against a
single file at one time, you can omit this parameter. In this case, the file number
returned by AWAITIO uniquely identifies the I/O operation that was completed.
If you opened the line server for wait I/O operations, omit this parameter.
Considerations The CONTROL procedure transmits an end-of-file message, an abort transmission
message, or terminates the sessions with the host and stops the line server. If the
subdevice was opened for nowait I/O, you must call AWAITIO to complete the
CONTROL I/O operation.