The STDSYS option specifies that the compiler should cause the SYSPRINT file to be equated to the C stdout file and the SYSIN file to be equated to the C stdin file.
Note: Under the LP(64) option, the STDSYS option is
ignored; effectively, STDSYS is always on.
.-NOSTDSYS-. >>-+-STDSYS---+------------------------------------------------><
Using the STDSYS option might make it easier to develop and debug a mixed PL/I and C application.
When SYSPRINT is equated to stdout, its LINESIZE cannot be greater than 132 (the largest value allowed by C).