Legacy Code interface - asynchronous callaback & __pin pointer

Sai Kit Tong

I have to interface managed application with my legacy dll. I have employed
the wrapper approach but I have to deal with the asynchronous callback from
the legacy dll, which likely goes through a thread other than the initial
calling thread. I got the idea from MSDN and other responses from this group
by using the delegate. However, for garabage collection issue, I need to pin
the delegate. Since my callback is asynchronous, I have been thinking about
create that __pin pointer within my wrapper and route the callback
through the wrapper class member function. However, .NET doesn't allow a
__pin pointer data member. What should be the proper practice to prevent
that callback delegate from being moved by garbage collection? The callback
existance have to last for the lifetime of the application - HW events.

Nov 15 '05 #1

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2097

Jeffrey Tan[MSFT]

Hi Sai,

In C#, I think you can use Fixed statement to get this down.

In Managed C++, you may use GCHandler to instead.

Best regards,
Jeffrey Tan
Microsoft Online Partner Support
Get Secure! - www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.

--------------------
| From: "Sai Kit Tong" <sk****@mmm.com >
| Subject: Legacy Code interface - asynchronous callaback & __pin pointer
| Date: Fri, 26 Sep 2003 10:44:26 -0500
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| X-Tomcat-NG: microsoft.publi c.dotnet.langua ges.csharp
|
| I have to interface managed application with my legacy dll. I have
employed
| the wrapper approach but I have to deal with the asynchronous callback
from
| the legacy dll, which likely goes through a thread other than the initial
| calling thread. I got the idea from MSDN and other responses from this
group
| by using the delegate. However, for garabage collection issue, I need to
pin
| the delegate. Since my callback is asynchronous, I have been thinking
about
| create that __pin pointer within my wrapper and route the callback
| through the wrapper class member function. However, .NET doesn't allow a
| __pin pointer data member. What should be the proper practice to prevent
| that callback delegate from being moved by garbage collection? The
callback
| existance have to last for the lifetime of the application - HW events.
|
|
|

Nov 15 '05 #2

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