> > > We could of course mutex every call to every external function. Then
we
> > > could be reasonably sure it would work, and at the same time we could
be
> > > sure that it was much slower than running it non-threaded.
> >
> > Any crash in an area protected by mutex would leave this mutex in
> > non-released state and all the rest threads trying to access that area
would
> > be blocked forever.
>
> A crash in a multi-threaded program most likely leads to the
> termination of the process, so this is a non-issue.
Okay. Suppose it's the best solution to avoid hangs.... :-)
> > BTW, is there any way for checking if a library does not create nor use
any
> > global variables ? May be just running nm with non-stripped .so objects
and
> > inspecting the resulting list ? Any other ideas ?
>
> nm displays global variables, including static function-scope
> variables. However, you cannot discern whether their use is
> save unless you audit the source code.
I agree but I meant different thing.
Everybody understand that sources must be audited but nobody want to do it
just because
they are too big and all the process would be just wasting the time. At
least withought
cliear understanding what to do after a snapshot is audited. Nobody would
like to do the same work twice.
Look, if a library (or function) does not use global variables nor call to
other functions that are explicitly marked as a
non-reentrant (should a list be opened for it?), this library can be safely
used in multithreaded
environment and thus the list of remained code to be audited
can be made fewer. Isn't it ? Don't you agree that it's nearly impossible to
audit all the code including
all the extensions. Even if anybody audited a particular snapshot of all
sources what to do with it
after other people have made modifications ? I believe there must be an
automated process that
should be tightly integrated in to building scripts. As a result we should
get a list of all functions with
one of the following "CLEAR" "TO BE AUDITED" "NON REENTRANT".
Any further ideas ?
-dmitri.
