This happens rarely in one of our older release versions of our software when running several instances concurrently:
forrtl: severe (32): invalid logical unit number, unit -221, file unknown
Image PC Routine Line Source
libifcoremd.dll 00007FFDC6BA5393 Unknown Unknown Unknown
sim.exe 00007FF7D9C617EC Unknown Unknown Unknown
sim.exe 00007FF7D99F104A Unknown Unknown Unknown
sim.exe 00007FF7DA174B92 Unknown Unknown Unknown
sim.exe 00007FF7DA1CD054 Unknown Unknown Unknown
KERNEL32.dll 00007FFE45AE7034 Unknown Unknown Unknown
ntdll.dll 00007FFE46902651 Unknown Unknown Unknown
Now, I believe the unit number -221 is the (NEWUNIT=) number for the log file, which is normally opened as CON, sharing violation perhaps?
Needless to say, rerunning the failing simulation on its own succeeds
The program was built with XE2019U5.
BTW, the current online documentation states
severe (32): Invalid logical unit number
FOR$IOS_INVLOGUNI. A logical unit number greater than 2,147,483,647 or less than zero was used in an I/O statement.
This needs updating to reflect the fact that NEWUNIT= returns a -ve unit number.
