Can I check for invalid TCustomWinSocket pointers?

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3 total messages Started by Lesley Anne Mon, 09 Oct 2006 17:52

#1830

Author: Lesley Anne
Date: Mon, 09 Oct 2006 17:52

10 lines
1557 bytes

I have a TServerSocket that gets queries from client connections and sends a 
response back to the socket that requested it.  The problem is that it often 
has to check external databases before it can formulate its response, so 
there can be a brief delay before it has something to send back.  If during 
that time the client has disconnected, it causes an access violation when I 
try to send back the response to a socket that no longer exists.

I'd like to be able to check whether my TCustomWinSocket* still points to a 
valid active socket before I try sending the response to it.  Is there a 
good way to do that?

Re: Can I check for invalid TCustomWinSocket pointers?

#1832

Author: Remy Lebeau (TeamB)
Date: Mon, 09 Oct 2006 19:40

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1540 bytes

"Lesley Anne" <mspfila-ng@yahoo.com> wrote in message
news:452a8c67$1@newsgroups.borland.com...

> I'd like to be able to check whether my TCustomWinSocket* still
> points to a valid active socket before I try sending the response to it.
> Is there a good way to do that?

The only way to validate the pointer is to see if it still exists in the
server's Connection's list.  Otherwise, you will have to update your code to
set your stored pointers to NULL when the OnDisconnect event occurs, and
then have your database code check for NULL before writing to the socket.


Gambit

Re: Can I check for invalid TCustomWinSocket pointers?

#1833

Author: Lesley Anne
Date: Mon, 09 Oct 2006 21:17

20 lines
1919 bytes

Remy Lebeau (TeamB) wrote:
>
> The only way to validate the pointer is to see if it still exists
> in the server's Connection's list.

OK, thanks.  I added a function to check for it that way and it seems to 
work.

> Otherwise, you will have to update your code to set your
> stored pointers to NULL when the OnDisconnect event occurs, and then
> have your database code check for NULL before writing to the socket.

The search for matching pointers is a little more complicated there and 
would require additional indexing on my database of outstanding 
transactions, so I'm going to start off with the other method.  This is 
worth keeping in mind, though, because I should be getting more response 
events than disconnect events.  If I need to start fine tuning this app for 
throughput issues, I'll check whether I get better performance by updating 
pointers on the (less frequent) OnDisconnect event.

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