How to compile code from stdin?

The code is quite simple :

test$ cat test.cpp

int main()
{
}

Is there a way to compile the code that is coming from a standard output?

I have tried this :

cat test.cpp | g++ -

and some variations, but none produced executable.

Just some clarifications. I have a program which preprocess a file, and produces another file which I want to compile. I thought about not creating this intermediate file, but to instead produce the object file directly.