Question

I have a method where I create objects on the heap and return a boolean which indicates if it went well or not.
I am not 100% sure about my bool assignments though in (1); is this legal to do?

    bool ret = true;

    if (ret = !mRenderBackend)     // make sure mRenderBackend is NULL
    {
        if (mEngineSettings.GetRenderBackend() == OPENGL)
            ret = mRenderBackend = mMemoryAllocator.AllocateObject<RenderOpenGL>();    // (1). AllocateObject returns either NULL or object address
        }

    return ret;

Thanks

Answer 1

You don’t really need the bool at all, it sort of makes it harder to follow. I would personally do something like,

if (mRenderBackend == NULL)     // make sure mRenderBackend is NULL
{
    if (mEngineSettings.GetRenderBackend() == OPENGL)
        mRenderBackend = mMemoryAllocator.AllocateObject<RenderOpenGL>();    // (1). AllocateObject returns either NULL or object address
    }

return (mRenderBackend != NULL);