Portability, Migration Considerations - HP A4500A - VMEbus Single Board Computer 744 Motherboard Programmer's Manual

Programming Guide
2. Manage the A/P Environment
Application Contexts (AP_CNTX_NAME)
Associations must negotiate the application contexts used. The initiator
proposes a service or services to run, and the responder must reply to
accept or reject the context. This is a mandatory parameter in the OSI
ACSE layer. For more information, refer to the OSI ACSE standard (ISO
8649, 8650).
Presentation Contexts (AP_PCDL)
The presentation context definition list (PCDL) is a list of presentation
contexts. Each presentation context consists of a unique presentation
context id, an abstract syntax and one or more transfer syntaxes.
Processes must negotiate the PCDLs used. The initiator proposes
contexts using the AP_PCDL attribute. The responder returns the result
for each proposed item with the status of ACCPT, USER_REJ or
PROV_REJ in the AP_PCDRL attribute before sending the
A_ASSOC_RSP primitive. An application can use ap_get_env() on
AP_PCDRL to find out the status and reason for each proposed item.
After a connection has been established, AP_DCS contains all acceptable
presentation contexts by both the initiator and responder sides.

Portability, Migration Considerations

To ease the migration of your applications as the standards evolve, the
following items should be considered:
• Set the AP_LIB_SEL attribute before any other attributes. This
attribute indicates which version of the A/P library will be used for
the process. This implementation currently only supports one.
However, as the A/P specification evolves, others may be supported.
• In future releases, the A/P interface will be modified to reflect the
X/OPEN ACSE/Presentation API Interface (XAP) once the standard
is approved and finalized. If you expect to migrate to XAP, the
following coding guidelines can help you:
• Always include the A/P library: ap_lib.h in your code that uses
ap_xxx() calls and A/P data structures.
• Isolate and minimize the code using ap_xxx() calls and A/P data
structures.
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