Accessing Files Programmer's Guide (32650-90885)

78 Chapter3
Specifying a File Designation
System-Defined Files
You could enter the following commands:
FILE INFILE=$STDIN
FILE OUTFILE=$STDLIST
RUN MYPROG
Input/Output sets
All file designators can be classified as those used for input files (Input Set), or those used
for output files (Output Set). For your convenience, these sets are summarized inTable 3-2.
on page 78 and Table 3-3. on page 78
An input file and a list file are said to be interactive if a real-time dialog can be established
between a program and a person using the list file as a channel for programmatic requests,
with appropriate responses from a person using the input file. For example, an input file
and a list file opened to the same teleprinting terminal (for a session) would constitute an
interactive pair. An input file and a list file are said to be duplicative when input from the
Table 3-2. Input Set
File Designator Function/Meaning
$STDIN Job/session input device.
$STDINX Job/session input device with commands allowed.
$OLDPASS Last $NEWPASS file closed. Discussed in the following pages.
$NULL Constantly empty file that returns end-of-file indication when read.
* formaldesignator Back reference to a previously defined file.
filereference File name, and perhaps account and group names and lockword. May
be a temporary file created in current job/session, created and saved in
any job/session.
Table 3-3. Output Set
File Designator Function/Meaning
$STDLIST Job/session list device.
$OLDPASS Last file passed. Discussed in following pages.
$NEWPASS New temporary file to be passed. Discussed in the following pages.
$NULL Constantly empty files that returns end-of-file indication when read.
* formaldesignator Back reference to a previously defined file.
filereference File name, and perhaps account and group names and lockword.
Unless you specify otherwise, this is a temporary file residing on disk
that is destroyed on termination of the creating program. If closed as a
temporary file, it is purged at the end of the job/session. If closed as a
permanent file, it is saved until you purge it.