50 Chapter 4
Programming Guide
2. Manage the A/P Environment
On the other hand, when the connection indication is received by the
other process, it is established as the responder, and can no longer issue
a connection request. The AP_ROLE_CURRENT is automatically set to
AP_RESPONDER.
If you decide to have a process act as a responder or initiator, you can set
the AP_ROLE_ALLOWED attribute using the A/P environment call:
ap_set_env(fd,AP_ROLE_ALLOWED,val)
Programs can be managed by designating the paired programs as
Initiator and Responder. See manpages for example programs.
Setting AP_ROLE_ALLOWED only affects the ability to send and
receive a connection request. Other primitives, such as P_DATA_IND,
are not controlled by the AP_ROLE_ALLOWED attribute.
CAUTION The initiator and responder roles must be established before binding the
communication endpoint to the local presentation address (in the
AP_UNBOUND state). Any change in AP_ROLE_ALLOWED after
binding is ignored.
Determine Address Handling
Before a communication endpoint can be used in an ACSE/Presentation
application, a unique presentation address must be assigned (or bound)
to it.
The presentation address consists of a presentation selector, session
selector, transport selector, and a n optional network service access point
(NSAP).
APRI also supports the binding of the local presentation address without
specifying a network address. This allows a single responder to receive
association indications for any of the subnetworks configured on an HP
OTS/9000 system. To use this feature, when setting the local address
through the AP_BIND_PADDR environment attribute, set the n_nsaps
field of the ap_paddr_t structure to zero. When this feature is used, no
local NSAP information need be provided in the ap_paddr_t structure.
Once a communication endpoint has been created by calling ap_open(),
and the initiator and responder roles have been established or explicitly
assigned using ap_set_env() with the AP_ROLE_ALLOWED primitive,
the endpoint is bound to the presentation address using the A/P
environment call
To Next Page
Loading...
Need help?
General