Bug with multiple stdio streams on one descriptor, FIX

[kwh at bentley.UUCP]

In article <562 at stride.stride.UUCP> stride!bruce (Bruce Robertson) writes:
>The problem is, the table is referenced like this:
>	_bufendtab[(p)->_file]
>where `p' is your FILE pointer.  This is wrong.  What you really
>want to do is reference the table like this:
>	_bufendtab[(p) - &_iob[0]]
>which associates slots in the table of pointers with slots in
>the table of _iob structures.

This assumes that all objects of type FILE are in the _iob[] array.
This is not necessarily the case; e.g. there is an auto variable of type
FILE (not FILE*) in sprintf(); there may be others.

Are you sure that having two streams on one descriptor is legal?  Is there
any documentation that explicitly permits or forbids it?

Now, the *real* question.  Why is _bufendtab[] in a separate array, rather
than being another field in the FILE structure where it seems to belong?

Karl W. Z. Heuer (ihnp4!bentley!kwh), The Walking Lint