Porting Guide

##How to port eRPC to use different infrastructure Infrastructure uses the advantages of C++ inheritance. Each part of the infrastructure has declared the interface in the header file, and implementation is done by inheriting the interface from this header file with it's own implementation. Interfaces and their implementations can be found in erpc/erpc_c/infra or erpc/erpc_c/transport.

Client: Client side-specific interface is declared and defined in erpc/erpc_c/infra/erpc_client_manager.h. Base implementation of interface-specific code is placed in erpc/erpc_c/infra/erpc_client_manager.cpp. Placed in same directory are the erpc_arbitrated_client_manager.h and erpc_arbitrated_client_manager.cpp files, which implement interfaces in a way to use the server and client on one side of the application and server, and client on the second side of the application. This is the extended use of eRPC to the bidirectional communication.

Server: Server side-specific interface is declared in erpc/erpc_c/infra/erpc_server.h and defined in erpc/erpc_c/infra/erpc_server.cpp. Interface-specific basic implementation is stored in the same directory in the erpc_simple_server.h and erpc_simple_server.cpp files.

Codec: For reading/writing to/from message buffers is used in the interface declared in the erpc/erpc_c/infra/erpc_codec.h file. Basic implementation of codec interface is stored in the same directory in the erpc_basic_codec.h and erpc_basic_codec.cpp files.

Message buffer: For sending and receiving data, used message buffers are declared in erpc/erpc_c/infra/erpc_message_buffer.h and defined in erpc/erpc_c/infra/erpc_message_buffer.cpp. The header file also contains an interface for creating and disposing these message buffers.

Transport: For adding a new transport type, the new transport layer needs to inherit and implement the interface from erpc/erpc_c/infra/erpc_transport.h. Implementations are stored in erpc/erpc_c/transport. In erpc/erpc_c/infra/erpc_transport.h can also be found in erpc_framed_transport.h and erpc_framed_transport.cpp, which implements the transport interface for framed type transports. The erpc_transport_arbitrator.h and erpc_transport_arbitrator.cpp files are also placed here. These implement the interface in a way to use the server and client on one side of the application and the server and client on the second side of application. This is an extended use of eRPC to the bidirectional communication.

##How to port eRPC to a different operating system The eRPC is designed to work under a different operating system. Port-specific code is placed in the erpc/erpc_c/port directory. Config: File erpc_config_internal.h sets the eRPC config macro definitions based on the used operating system. Port: File erpc_port.h is used for porting functions for allocation and freeing memory. Implementation is stored in the source file, with name extended with the operating system-specific word. Source files also overload C++ new and delete methods. Threading: File erpc_threading.h is used for supporting threading. Implementation is stored in the source file with name extended with the operating system-specific word. Serial: Files erpc_serial.h and erpc_serial.cpp contains port serial communication to macOS®, Linux® OS, and Windows® OS.

##How to port eRPC for C-programmers / How to set eRPC application

The eRPC is designed to use C++ program language. However, it can be used by C-type programmers using C-wrapper functions. This chapter also shows what programmers need to do to get eRPC application working. Each interface specific object is defined as global using the ManuallyConstructed template class stored in erpc/erpc_c/infra/erpc_manually_constructed.h. This template is used for creating space for the C++ object without calling any object-specific things, like Constructor. This prevents static initialization in the application before calling the main. The object is assigned to created memory space calling method construct(). Objects do not need use this class, but it is recommended. C-wrapper functions are stored in erpc/erpc_c/setup directory. Common: Common thing to setup is to set the transport type and the message buffer factory type.

• Declarations of transport init functions are stored in erpc_transport_setup.h file. The source file is for each transport layer different. The name of the source file is erpc_setup_<transport_name>.cpp.
• Declarations of message buffer factory init functions are stored in erpc_mbf_setup.h file. The Source file is for each message buffer factory type different. The name of the source file is erpc_setup_<mbf>.cpp.

Client: C-wrapper functions for client are declared in erpc_client_setup.h and defined in erpc_client_setup.cpp. The ClientManager, BasicMessageBufferFactory, and BasicCodecFactory sets are located here. It is important to have *ClientManager g_client; as the global declaration, because the client shim code needs to access it. In init function is every type of infrastructure set to ClientManager object. In deinit function are called destructors of initialized objects. In function erpc_client_set_error_handler can be set error handling functions. This means that when an error occurs on the client side, this is the only way the eRPC part of application can inform the client part of application that the error occurred. When an error occurs, a set function is called.

Special type of ClientManager is ArbitratedClientManager. For using the application as bidirectional, include erpc_arbitrated_client_setup.h and erpc_arbitrated_client_setup.cpp instead of erpc_client_setup.h and erpc_client_setup.cpp. Setting ArbitratedClientManager is similar to setting the ClientManager. It is extended to set BasicCodec and TransportArbitrator objects. To the TransportArbitrator object is set transport and codec object. The rest are set to the ArbitratedClientManager, including the TransportArbitrator object. This TransportArbitrator object needs be set as the transport to server for this side application.

Server: Setting the server application is similar to setting the client application. C-wrapper functions for the server are declared in erpc_server_setup.h and defined in erpc_server_setup.cpp. Here are the set SimpleServer, transport, message buffer factory, and BasicCodecFactory. It is important to have *SimpleServer g_server; as the global declaration because other server functions need to access it. In init function, every type of infrastructure is set to SimpleServer object. In deinit function are called destructors of initialized objects. For adding service from generated shim code, use the erpc_add_service_to_server function. For running the server in an infinity loop, use the erpc_server_run function. When an error occurs, this method returns an error status type. For using the polling server, use method erpc_server_poll. This method returns an error status type. For the stop running server, call the erpc_server_stop function.