[Xapian-discuss] Threaded test (in C++) to reproduce our database problems

[Olly Betts]

On Thu, Jun 17, 2004 at 02:29:29PM +0100, Olly Betts wrote:
> A quick poke in /usr/include suggests the only likely issue might be
> errno which uses a per-thread version if _LIBC_REENTRANT is defined (but
> nothing seems to define that).

Looking more closely, it also uses it if _LIBC is *NOT* defined.  And it
isn't by default.  Checking preprocessed output confirms this.

> And it might also explain the whole problem.  If EINTR is overwritten 
> by some other error value at the wrong moment, reading or writing a
> block might incorrectly be thought to have failed.  CVS HEAD changes
> the quartz backend to stop it doing a full close and reopen of all
> the btree tables on flush(), which probably makes it a lot less likely
> to encounter this situation.

This explanation seems to fit so well, except that it appears errno *is*
per-thread.

> So try configuring 0.8.0 with:
> 
> ./configure CPPFLAGS=-D_LIBC_REENTRANT
> 
> I'll give this a whirl too.

Doesn't make a difference - 0.8.0 still fails.  Which is what I would
expect since _LIBC isn't defined...

Hmm.

Cheers,
    Olly