Hi,

have a look at the attached C module, you are welcome to use this.

You will need to change the includes to suit your needs.

The apache httpd sources are a good place to look for this sort of thing
as they have done it very well

hope this helps

Andy

On Fri, 2004-11-19 at 06:48, hzhijun wrote:
> Hi, Frank
> I really a newbie to the OpenSSL callback usage. If I set the locak callback,
> What should be done in the callback function?
> Thanks
>
> > hzhijun wrote:
> > > i don't think it need to set locking_function since i did not use any shared datastructures in my application.
> > you may not, but the OpenSSL-LIB does definitly. And as soon as your
> > application gets multithreaded, you always risk a race conditions which
> > not neccessarily could cause a crash, but which could.
> >
> > Although OpenSSL uses many global data structures, all i have to do is
> > use the proper compiler to build OpenSSL with multithread options.
> > ...for having it built with multithread-supprt this is sufficient, but
> > as soon as you know your application gets multithreaded (whether you
> > spawn threads by your own or you use some library-functions which does
> > this for you (implicitly)...for example using the multi-interface from
> > libcurl should be enough) it is a must to "give" the OpenSSL-Lib the
> > callbacks to be able to lock their global datastructures, nevertheless
> > your app would work without the locks very often or even nearly always,
> > it is not relieable and not a good way to code. You probably/hopefully
> > would use locking mechanism to protect data-access to your global
> > datastrucutres if you would had some in *your* multithreaded
> > application. Just because you dont't see the library's code which spawns
> > threads and makes accesses to global data from this threads, it ist no
> > good idea not to lock the accesses. You just risk having the whole
> > application crashed in some day. And in this day you even might have
> > forgotten about the locking issue, so I predict you wont' find the cause
> > or even some indicators for it.
> >
> > Anyway, best wishes. If you need some help on how to provide those
> > callbacks in a propriate way, just let know.
> >
> > Ciao, Frank.

-- 
Andy Hobbs <andy_at_hobbs.uk.net>