Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Using SYSIN and SYSPRINT files

If you code GET or PUT statements without the FILE option, PL/I contextually assumes file SYSIN and SYSPRINT, respectively.

If you do not declare SYSPRINT, PL/I gives the file the attribute PRINT in addition to the normal default attributes; the complete set of attributes is:

  file stream print external

Since SYSPRINT is a PRINT file, a default line size of 120 characters is applied when the file is opened.

You can override the attributes given to SYSPRINT by PL/I by explicitly declaring or opening the file. However, when SYSPRINT is declared or opened as a STREAM OUTPUT file, the PRINT attribute is applied by default unless the INTERNAL attribute is also declared.

PL/I does not supply any special attributes for the input file SYSIN; if you do not declare it, it receives only the default attributes.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide