Re: Design Receive and transmit UDP packets

"ScottMcP [MVP]" <>
Thu, 9 Feb 2012 15:06:14 -0800 (PST)
On Feb 9, 12:29 pm, Hezi Halifa <> wrote:

I have a windows tool which runs on a PC, and transmit and receive packet=

s to/from a some target machine. the tool needs to send packets at some con=
stant delay (e.g 5 milisecond ).

packets are being sent to the PC from the target every 1.25 miliseconds.

In order to be close to a 5 milisecond delay, I used multimedia timer. on=

 the receive side, I intend to use the MFC CAsyncSocket::OnReceive

Question: what happens if packet is received, but multimedia timer cal=

lback is executing at that time?

thank you


I think you will find that the multimedia timer callback is called on
a system thread. But that recollection is from memory and I do not see
that mentioned in the current MSDN documentation. If it is called on
a system thread then you could get concurrect callback and OnReceive
because they run in separate threads.

OnReceive is a message handler function, called in the thread that
created the socket. So it will wait until your thread returns to the
MFC message pump to call you.

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