Determining Redirection: HPSTDIN and HPSTDLIST

CIOR provides two predefined MPE/iX string variables to reflect the state of I/O redirection. These variables can be used within User Commands or programs that need to detect if their input or output has been redirected. HPSTDIN will default to the string "$STDIN". HPSTDLIST will default to the string value "$STDLIST". These values also indicate whether or not input or output is currently redirected. If input is redirected, HPSTDIN will contain the name of the file to which input has been redirected. If input has been redirected through a file equation backreference, HPSTDIN will contain the formal file designator of the file equation. Similarly, HPSTDLIST will contain the filename or formal file designator of the file or file equation to which output has been redirected.