I have a UDC like this, but I also run a short program that calculates a
checksum on the file and puts it in a system variable. Someone can change
the access and mod dates to the file and the checksum guarantees the source
code matches.
....
setvar _cob_parm _cob_parm+$01
file cobtext=!text
SETVAR _COB_INFO _COB_INFO + "$VERSION '" + FINFO("!TEXT","FULLFNAME") &
+ " !HPDATEF !HPTIMEF'"
endif
if "!list" <> "" then
....