Question

I need to send/receive data between two processes. One of them will be using Qt (4 or 5).
That process will be running all the time (like a background process).

The other process will be launched and then it should be able to send argv to the
first process and receive some answer from it.

The second process must startup as fast as possible so using QtCore is kind of a last resourse. Meaning I need it to be as small and fast as possible, so I’d need to use plain
C/C++ without any external libraries.

Any ideas how it could be done?

If that’s not possible, I’ll have to use QtCore in the second process. Do you know how much
slower it would be because of QtCore vs plain C/C++? (in terms of startup time).

Regards

EDIT:

I can’t use QBus as this must be Mac/Linux/Windows compatible.

Answer 1

If it needs to be fully cross platform compatible your best bet is likely to be named sockets/named pipes, which should work on each platform. Should take you to the information you need for the socket setup. You’ll still need some network handling code in your pure C++ application, but it should be significantly less overhead than Qt-Core and Qt-Network.

You could also do it with shared memory, but I prefer the socket method for simplicity.