11.2 DLL InterfaceThe communication with the polarizationNAVIGATORTM is imple-mented using a DLL interface.The name of the DLL is PolNavClient.dll. It is installed in theWINDOWS/SYSTEM32 directory during the setup process.There are two exported functions. The C function prototypes are asfollows:int __stdcall PolNav_SendCommand(const char *Target,const char *Command,char *Response,int MaxLen,int &ResponseLen);int __stdcall PolNav_ReadResponse(int iStart,int iLength,char *Response,int MaxLen,int &ResponseLen);PolNav SendCommandCommands:This function sends a command to the Navigator and retrieves the re-sponse.Variables: Parameter DescriptionTarget Target Name (section 11.3)Command The command string to be sent to the Navigator.Response Pointer to a buffer reserved for the response. Thecalling application has to allocate enough mem-ory to receive the response. The response is a0-terminated string.MaxLen The size of the allocated response buffer.ResponseLen Here, the total length of the response is returned.If the response does not fit into the allocatedbuffer, only the first part is copied into the re-sponse buffer. Use PolNav ReadResponse to ac-cess smaller fractions of the response.Return Value The return value is an Error Codes (section 15.3). A ”0” indicates successful operation.PolNav ReadResponseCommands:This function sends a command to the Navigator and retrieves the re-sponse.This function accesses fractions of the last received response. Particularlyin VBA, strings cannot be longer than 32767 characters. Thus you willhave to access longer response strings using this function.Variables:A1XXX/A2XXX/A3XXX User Guide 87
