Function that returns a Structure
Since you're (probably) using a C++ compiler, it's usually easier to declare structures like this:



struct CarSpeed
{
    int fr, fl, br, bl;
};


(Note that there's no need for typedef.)

You can then return an instance of it directly from your function:

CarSpeed ReadSpeed()
{
    CarSpeed data;

    data.fr = ...;
    data.fl = ...;
    data.br = ...;
    data.bl = ...;

    return data;
}


You can call it from another function like this:

CarSpeed speed = ReadSpeed();


That will copy the contents of the structure into an object called speed. In this example, it's an 8 byte structure so it's a non-trivial copy. That shouldn't be a big problem unless you're calling it very frequently though.

As noted in another answer, using a pointer (or a reference) can be more efficient if necessary.