Question

Hokay so I have an application where I need some IPC… I’m thinking named pipes are the way to go because they are so easy to use.

Anyways, I have a question about how to handle dynamic memory using named pipes.

Say I have a class such as this:

class MyTestClass {
public:
    MyTestClass() { _data = new int(4); }

    int GetData() { return *_data; }
    int GetData2() { return _data2; }

private:
    int* _data;
    int _data2;
};

Now when I create a buffer full of MyTestClass objects then send them over the pipe, I’m obviously losing _data in the destination process and getting garbage. Is there some strategy to this that I should use? I can use value types for simple cases, but for many complex classes I need to use some sort of dynamic memory and I like pointers.

Or, should I just look at using shared memory instead? Thanks

Answer 1

Both named pipes and shared memory have similar issues: You need to serialize the contents of the structure into the on the sending side and deserialize the structure from the on the receiving side.

The serialization process is essentially identical whether you’re using named pipes or shared memory. For embedded pointers (like _data and _data2) you need to serialize the contents of the pointer in a consistent fashion.

There are lots of serialization strategies that you could use, depending on how your structures are laid out in memory and how efficient your IPC has to be. Or you could use DCE RPC and let the RPC marshaling code handle the complexities for you.