For compatibility with
SAS on other platforms, the FILEEXT= system option enables you to
write portable SAS programs that run on systems that either support
or do not support file extensions.
Portable SAS programs
can access external files with file extensions when you run those
programs in environments such as Windows and UNIX. When you run those
programs in
z/OS, and when the program accesses members in partitioned
data sets, the value of FILEEXT= determines how the file extensions
are interpreted.
Member names in partitioned
data sets must consist of one to eight alphanumeric characters starting
with a letter or with one of the following national characters: $,
#, @. A member name extension is an optional part of the member name
that follows a period.