| SAS Component Language: Reference |
To establish the communication between SAS software and an external
file, you must assign a fileref to the file with the FILENAME function. If
an application requires that users specify the name of the physical file,
then create a block of SCL code labeled with a window variable name to run
only when a user enters a filename in that field. You can also put the FILENAME
function in the MAIN section so that it executes after a user specifies the
filename. In this case, add a statement to check that the field containing
the filename has been modified so that the FILENAME function does not run
every time the MAIN section runs. When a program can specify the name of the
physical file without user input, put the function in the initialization section
so that the function executes only once, before the window opens.
You can also assign filerefs outside of an application
when files are used by all or large parts of your application. You assign
filerefs to these files by using the FILENAME statement in base SAS in the
application's start-up file (the autoexec file). For more information about
assigning filerefs, see the SAS documentation for your operating environment.
There are other SCL functions that you can use to manipulate
filerefs. Use these functions to prevent programs from terminating prematurely
because of possible errors (for example, a fileref is already assigned or
a physical file does not exist).
- Use the FILEREF function to verify that a fileref
has been assigned to a physical file for the current SAS session or process.
- Use the FEXIST function to verify that the file
associated with a specified fileref exists.
- Use the FILEEXIST function to verify that the
file associated with a physical name exists.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
