Sys Tec Electronic GW-003 - Dynamic Linked Library Ethcan.dll; The Concept of the Ethcan.dll

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Software Support

7.3 Dynamic Linked Library EthCan.Dll

The Dynamic Linked Library (EthCAN.Dll) is a function library for

application programs. It serves as an interface between the Windows

socket and an application program. It manages the connected CAN-

Ethernet Gateway devices and converts the CAN messages in IP

packets and vice versa.

In order to include the DLL to a project, the EthCan.Lib must also be

included. The DLL is then loaded automatically when the application

program is started. If the LIB is not linked to the project, then the DLL

has to be loaded with the Windows function LoadLibrary() and the

library function has to be added with the function GetProcAdress().

The STDCALL directive of the DLL's call function ensures a

standardized call interface for the user. This guarantees that someone

familiar with another programming language (Pascal, ...) can also use

these functions.

7.3.1 The Concept of the EthCan.Dll

With the EthCan.Dll up to 5 CAN-Ethernet Gateways can be

addressed simultaneously within an application. Furthermore, it is also

possible to access 5 CAN-Ethernet Gateways from a remote

application as long as they have the same remote address (as shown in

application 1). This is because multiple interfaces can be connected to

the CAN-Ethernet Gateway at once, so that connections from multiple

applications are possible. However, it is not possible to establish

multiple connections to one and the same CAN-Ethernet Gateway

from a single application.

When the DLL is used, two software states are generated for each

CAN-Ethernet Gateway. After the application program has been

started and the DLL has been loaded, the software will be in the state

DLL_INIT, whereby all necessary resources for the DLL are created.

If the library function EthCanInitHardware() is called, then the

software will change to the HW_INIT state. All resources that are

necessary for communication with the CAN-Ethernet Gateway are

provided here. With the library function EthCanDeinitHardware() it