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visual-c++message-queue
Carlos
Carlos

Reputation: 167

Message Queue in visual c++

Can multiple processes communicate through Message Queues or is it only for multiple thread communication ? I want to let two different processes communicate. I don t want to use shared memory because of some reasons. I want to use message queues instead. Is is doable ?

Upvotes: 0

Views: 2131

Answers (2)

Cody Gray
Cody Gray

Reputation: 244772

Yes, this is possible. Call the PostMessage function to add a message to the queue for a window, or PostThreadMessage to add a message to the queue for a thread. (Obviously, the thread must be running a message loop.)

The WM_COPYDATA message is explicitly designed for this purpose. It does the marshaling for you. Of course, it is a pretty basic form of marshaling: all it knows how to do is marshal a blob of bytes. It's your responsibility to interpret that blob of bytes into something useful.

There is a complete example of copying data between processes here on MSDN.

It is also worth pointing out that you don't even need WM_COPYDATA if the amount of information that you want to pass is so small that it will fit inside of wParam or lParam.

Upvotes: 1

harper
harper

Reputation: 13690

The Message Queing is a construct for inter process communication (IPC).

You can build a data construct in the memory of one process that even can implement a queue. This can be use for quick processing e.g. for Windows messages. This must be differentiated from MSMQ.

Upvotes: 0

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