Re: win32 design patterns

From:

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.language

Date:

Wed, 5 Mar 2008 09:37:43 -0600

Message-ID:

<#WwLDatfIHA.320@TK2MSFTNGP02.phx.gbl>

"Giovanni Dicanio" <giovanni.dicanio@invalid.com> wrote in message
news:ezC9cJtfIHA.4436@TK2MSFTNGP02.phx.gbl...

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam> ha scritto nel messaggio
news:Oq5I95sfIHA.1168@TK2MSFTNGP02.phx.gbl...

Nothing could be farther form the truth. Why do you think .NET
environment called "managed" after all? For exactly the reason that it
manages resources for you. .NET has garbage collector, wich can be tuned
to great extend. GC makes RAII irrlevant in most of the cases.

Nonsense. GC makes RAII irrelevant in only one case: memory is the only
resource.

So in C#, if a non-memory resource (like a file) is not "guarded" by a
'using' block, is this resource leaked if an exception is thrown??

Yes, it is leaked for some arbitrary period of time until (1) the GC runs,
determines that the resource owner is unreachable and (2) the finalizer
thread runs the finalizer. During that time (using the file example) it
will remain open and locked, so that subsequent access to the file may fail
depending on whether the GC has run yet. This non-deterministic cleanup
creates a race condition. An alternate example is, since the GC is
triggered by memory pressure, a database connection pool could be exhausted
by unreachable objects waiting to be finalized, but the GC will not run
because it doesn't know that resources are scarce and a collection is
needed.

Giovanni