In article wc$y$BBnrPm8EwuI@tcs02.demon.co.uk, Martin Liddle martin@tcs02.demon.co.uk writes
We (principally my colleagues Ron Jackson and George Brown) have done more testing. Most things look OK but they have discovered one apparent problem when writing to a file whose records are string(25). I am investigating but so far my attempts to produce a test program that shows the problem are failing (i.e. my test programs work as expected). Hence this is just a heads up of a possible problem and I'll put some more effort into understanding what is going on, hopefully tomorrow.
OK I now understand. This is not a compiler problem. I failed to understand how some code written by a colleague worked and hence my workaround for the inability to set capacity failed in this case. I now have a new work around that seems to do what I want.
Apologies for wasting everybody's time.