Windows Communication Dll For Pq-Link Protocol; Introduction; Interface - ABB RVT Serie Instrucciones De Instalación Y De Funcionamiento

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6 Windows Communication DLL for PQ-Link
protocol

6.1 Introduction

This document describes the interface of the Windows Communication DLL.
The interface is heavily based on the protocol described
This document will focus on the differences with the protocol. Indeed, to ease the life of
DLL user, some code has been added to handle annoying parts of the protocol.
Moreover, to be compatible with Visual Basic 6.0, some types have had to be modified
as VB does not support certain types (unsigned 16-bits integer for example).
The DLL allows communicating with the RVT through:
- a TCP/IP network connection
- the RVT USB serial interface

6.2 Interface

6.2.1 Introduction
All exported library functions follow some similar syntax:
COMMANDCLIENTDLL_API int __stdcall CommandClient_Fct(...);
The first item is defined as follows:
#ifdef COMMANDCLIENTDLL_EXPORTS
#define COMMANDCLIENTDLL_API __declspec(dllexport)
#else
#define COMMANDCLIENTDLL_API __declspec(dllimport)
#endif
The "COMMANDCLIENTDLL_EXPORTS" define is used within the DLL to make sure that
the functions get exported. When the DLL is used in an external program, it is not defined
and the functions are then imported from the DLL.
All functions return an integer providing an error code to the calling layer.
The "__stdcall" specifier is used to indicate that the calling convention to be used is the
standard one.
Special care has been taken so that the function names exported by the DLL are the same
as the ones defined above.
WARNING: in the rest of this chapter, "COMMANDCLIENTDLL_EXPORTS" and "__stdcall"
have been removed from the documentation to ease the reading. They are naturally
always present in the header file.
RVT communication ç Windows communication DLL for PQ-Link protocol - 67
Chapter 4 of this document.