SNAX/HLS Application Programming Manual

OPEN Verb
Application Prototyping and Simulation (APS) System
104707 Tandem Computers Incorporated 6–27
Open: HLS-OPEN Verb
(SF3)
The HLS-OPEN request is used to establish communication with your session partner.
This verb follows an HLS-ALLOCATE verb that allocated the session ID, identified the
name of the partner, and specified, by the PROFILE name, the options that govern the
session.
The HLS-OPEN request completes the establishment procedures by identifying the
name of the application, allowing for resynchronization of sequence numbers, and
permitting the sending of user data on the specialized SNA requests that are involved
in the establishment procedures.
The execution of this verb depends on the PROFILE options in effect. If the session is
declared as ACQUIRE, verb execution causes SNAX/HLS immediately to attempt to
establish communication with the session partner. This involves the transmission of
specialized SNA requests: BIND if your session is primary, and INIT-SELF if your
session is secondary. In either of these cases, you can specify an application name and
optional user text to be included on the request. The actual use of these fields depends
upon the standards imposed by your partner.
If the session is declared as ACCEPT, verb execution instead awaits a message from
your partner. This arriving message can be one of the two SNA requests: BIND if you
are secondary, or CINIT if your session is primary. In the latter case only, SNAX/HLS
responds to the CINIT by sending a BIND message bearing the application name and
user text you specify.
Note that the two modes of open are complementary; one partner must be in
ACQUIRE mode, and the other in ACCEPT mode. Furthermore, the accepting side
must be preconditioned (must be reading) before the acquiring side can establish the
session. The open mode of a PROFILE record can be found in the RDT listing, or by
the HLSCOM STATUS command once a session is active.