[Mono-list] Re: Consuming unmanged code, global/static variables, ASP.NET pages

[Chris Harris]

Robert,

This is exactly what I was wondering.  So it's safe to initialize this way,
all asp worker threads would have access to an initialized library.

Well that saves me a lot of work.

Thank you very much for your time,
Chris

On 2/23/06, Robert Jordan <robertj at gmx.net> wrote:
>
> Chris,
>
> > What about C# wrapper classes that were singletons and had locks that
> would
> > take care of race conditions, initializing the library in global?
>
> Now I understand what you are looking for: an entry point to
> initialize the lib. This entry point exists even for ASP.NET apps:
> it's the method
>
> protected void Application_Start(Object sender, EventArgs e)
>
> of global.asax
>
> But you can use a singleton for the initialization as well.
>
> Robert
>
> >
> > On 2/23/06, Robert Jordan <robertj at gmx.net> wrote:
> >> Chris,
> >>
> >>> Looking for some guidelines on consuming some of our library (in C)
> into
> >>> .NET for use with ASP.NET pages
> >>>
> >>> I'm concerned about our global and static variables that are needed in
> >> some
> >>> of our libraries.  In a single threaded C# application this would be
> no
> >>> problem.  Initialize the libraries at startup, destroy on close.
> >>>
> >>> But for ASP.NET pages, how would I handle initialization, since
> multiple
> >>> pages are being served at the same time making use of these libraries?
> >> Are your native libraries thread safe? If yes, you usually don't
> >> have to care about the initialization. If they are not: welcome to a
> >> world of pain.
> >>
> >>> Would I initiailze for each page request as needed in the C# code
> behind
> >>> page?  Or is this going to have problems when multiple requests are
> >> issued?
> >>
> >> It won't work. Go ahead and fix the native library. Everything
> >> else is a waste of time.
> >>
> >>> Also what about a function that contains a static variable?
> >> You have to rewrite them to use a TLS slot instead of the
> >> static variable. If the content of the static variable is
> >> thread invariant, a lock for its initialization might be sufficient.
> >>
> >> The same has to be done with static variables outside
> >> of functions as well.
> >>
> >>> Basically these are the questions I have, but I just can't find any
> >>> resources to explain how ASP.NET applications are threaded, and how it
> >> would
> >>> effect consumption of unmanaged libraries.  If anyone can even point
> me
> >> in
> >>> the right direction I'd be very grateful.
> >> The threading model of ASP.NET is quite straightforward for
> >> the developer: one cannot predict by which thread the request
> >> will be handled. This implies that the ASP.NET consumer has
> >> to deal with concurrency all the time.
> >>
> >> Robert
> >>
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