Com basic 1

1. First, distinguish three basic concepts (component, COM, and component object)

COM component is a software component designed according to com specifications. It can be used to form large-scale application software;

COM (Component Object Model) is about how to build components and how to build applications through componentsProgramA specification;

Component Object: Generally, a component is implemented by class, so this class object is called a component object.

 

Now it seems to be called COM components.

2,COM Component Interface, role

From the customer's point of view, the interface is the method that the component is exposed to the outside, so that the customer can access it;

From the component perspective, an interface is a set of function-related functions, or an interface is a list of projects that can be used for external services by the component.

 

3. The most basic interfaces of COM components

Iunknown, which has three pure virtual functions: QueryInterface, addref, and release;

 

4. Component Classification

In-process components: these components are implemented in DLL and run in the address space of the client program;

 

Out-of-process components: components running in EXE files are called out-of-process components, which are divided into two types:

Local components: they run on the same computer as the customer, but they have their own address space;

Remote component: it runs on a computer connected to the client instead of the same computer as the customer.

 

5. Source of COM components

If the defect occurs, you can check the information yourself. You are welcome to discuss it.