MPE/iX - CI Programming for Stability

July 18, 2008 HP World '01 60
UDCs vs. scripts
• option logon
• UDCs only (a script can be executed from an “option logon”
UDC)
• logon UDCs executed in this order:
• 1. System level 2. Account level 3. User level
(opposite of the non-logon execution order!)
• CI command search order:
• A. UDCs ( 1. User level 2. Account level 3. System level)
• thus UDCs can override built-in commands
• B. built-in MPE commands, e.g. LISTFILE
• C. script and program files. HPPATH variable used to qualify
unqualified filenames
• :XEQ command allows script to be same name as UDC or built-
in command, e.g. :xeq listf.scripts.sys