| SAS Component Language: Reference |
SCL lists support shared data environments. (Without a shared data environment,
if you wanted an entry to pass data to many other entries, you had to pass
the data explicitly in each CALL DISPLAY statement, or else you had to put
the values in macro variables. However, macro variables are limited in the
amount of data they can contain (only scalar values), and their names must
be valid SAS names.) By placing data in a shared data environment, other
programs and even other SAS applications can retrieve the data via a name.
These names can be any valid SCL string, and the value associated with a
name can be a numeric value, a character value, or an entire list.
The two kinds of shared data environments are implemented
with local SCL lists and global SCL lists.
Each SAS software application (such as an FSEDIT application,
or a SAS/AF application started with the AF command) maintains its own application
environment in a local environment list. You can store information that is
local to the application, but which you want to be shared among all of an
application's entries, in this local environment list. The function ENVLIST('L')
returns the list identifier of the environment list for the current application.
Other applications' lists are maintained in the memory of each application,
and even though two lists in different applications may have the same list
identifier, the lists are actually different. This is analogous to the same
SAS table identifier being used by different SAS applications: the identifier
actually refers to different SAS tables that are opened at different times.
There is also a global environment list that stores data that
can be shared across all SAS applications started in the same SAS session
or process. For example, one SAS application may place some data in the global
environment list and then close. Another application may then open and read
the data that was created by the first application. To access the global
environment list, use the list identifier returned by ENVLIST('G').
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
