Hi Juergen, I know the file was successfully opened, because I print the argument that is going to be passed to do the read, 2 0 16, and it has successfully fetched the file size.
The value error is strange, because it branches to the dyadic case only after using NC to check existence of the left argument to SVOPAIR. Then it gives a value error on PID, but if you print it after the function is suspended, it is 210. So something odd is clearly going on there, independent of what GNU APL's AP210 does or does not support. FILE_IO is clearly the better way to go. Being able to load shared libraries is much more useful than shared variables on modern machines. Regards, Mike
