Environment Variables : Environment Variables under CICS
Nonprogram-scope
environment variables are stored in a temporary storage queue, which exists
until it is manually deleted or the CICS region (or temporary storage) is
cold started. Thus, the lifetime of a queue can vary considerably. Some
sites cold start their regions every night. If CICS crashes during the day,
it could also be cold started at that time. Generally, environment variables
persist for the duration of a session connection (logon to logoff), but they
could persist between connections.
By default, the library uses the VTAM netname as a queue
name and only accesses the first record in the queue. The queue name is set
in the user-replaceable routine L$UEVQN. This routine enables a site to use
some other scheme for assigning a queue name, including the option of sharing
a single queue between all programs. See the source code in the SASC.SOURCE
data set (under OS/390) or the LSU MACLIB (under CMS) for complete details.
Because Temporary Storage is a shared facility on CICS,
some potential problems exist with the technique of using the VTAM netname
as a queue name. Some of those problems are:
Only program- and external-scope environment variables
are supported under CICS (that is, there is no support for permanent or lasting
environment variables). Note that for CICS, session scope is considered to
be the same as external or storage scope.
Environment variable names are limited in CICS to 254
characters, and values are limited to 255 characters.
SAS/C provides a transaction that enables you to inspect
and modify environment variables without writing a program to do so. You invoke
the transaction to set the environment variables of interest; then, in a separate
step, you invoke your application transaction. See the
SAS/C CICS User's Guide for more
information.
Copyright © 2001
by SAS Institute Inc., Cary, NC, USA. All rights reserved.
