Re: casyncsocket communication between service loaded dll and an exe

"Alexander Nickolov" <>
Tue, 1 May 2007 14:17:39 -0700
FYI, MFC is officially not supported in NT services.

Alexander Nickolov
Microsoft MVP [VC], MCSD

"r norman" <> wrote in message

On Tue, 1 May 2007 11:49:07 -0700, "Michael K. O'Neill"
<> wrote:

"Inna Raykhman" <> wrote in message

i have a process that runs as a service, that loads standard C dll
"A", that in turn loads mfc dll "B".

this dll "B" does Connect() in a class derived from CAsyncSocket, to
try and connect to another exe - exe "R", that runs on same machine as
a regular process. this exe "R" sees the connect and does Accept().

in dll "B" the onConnect() is never triggered. and the initial
Connect() always comes back with WSAEWOULDBLOCK.

when i test same setup by loading dll "B" from a test mfc app that i
wrote, everything works fine, onConnect is triggered every time and
everyone is happy.

are there any socket limitations to service processes?


CAsyncSocket only works if your process has a message loop (i.e., if it
services a message queue).

If your process does not have a message loop, then none of the OnXxxx()
functions like OnConnect() will ever be called.

Exactly. I have a service that uses CAsyncSocket which is created in
the InitInstance() of a class derived from CWinThread. That takes
care of the message loop nicely.

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