CRE Programmer's Guide

CRE Service Functions
Common Run-Time Environment (CRE) Programmer’s Guide—528146-004
6-35
CRE_Receive_Open_Close_
CHECKPOINTX, CHECKPOINTMANY, CHECKPOINTMANYX, and so forth. Note
that the CRE allocates enough space to accommodate the maximum number of
retained replies times the maximum number of requesters times the maximum
number of bytes per saved reply. For example:
Space_allocated := Maximum^requesters *
Maximum^syncdepth *
Maximum^reply;
Your program might be able to allocate less space if it can distinguish requests that
alter a database from requests that only return information without altering a
database. Your program might be able to allocate less space:
°
If it does not retain messages that do not update a database.
°
If it is not necessary that the program receive the same response to a
database query for each such query. If it is possible for a database to be
changed, however, by another process, two successive queries might return
different and inconsistent responses.
Specifying
Maximum^reply:
•
Maximum^reply specifies the maximum number of bytes in each message that
the CRE saves.
Specifying
Receive^depth:
•
You read messages by calling CRE_Receive_Read_ and reply to messages by
calling CRE_Receive_Write_. These functions correspond to the READUPDATEX
and REPLYX system procedures.
Specifying
Report^flags:
•
You can specify, on a message by message basis, which system messages you
want to receive. The CRE receives all system messages but returns to your
program only those messages that you specify in
Report^flags.
Table 6-5
on page 6-36 shows literals that you use to specify the messages you
want to receive. The literals shown in Table 6-5
are in the CREDECS file.