Appendix C: Creating C Components

Generate C component files

To write a C component, you need these C component files. You compile these C component files (or C source files) into a DLL.

Method skeletons file – this file contains method routines that read the parameters from the network and call the method. The method skeleton also sends the return status and output parameter data back to the client.
Method prototypes file – this file contains the method declarations only. This file is an included file in the method skeletons file and the method implementation template files.
Method implementation template files – these files contain the method and parameter declarations and an empty method definition. You enter any business logic into the empty method definition.

The graphic below illustrates how EAServer calls the DLL’s functions in response to a component methdod invocation:

Figure C-2: How a C component method is called

The sequence of events is:

The client invokes a method using the proxy or stub appropriate to the type of client. The stub or proxy sends the invocation information over the network to the server.
The method skeleton in the method skeletons file unmarshals the call and makes another call to the method implementation in the method implementation template file.
After the method executes, the method implementation returns the call to the method skeleton.
The method skeleton marshals the call and sends the call to the client.