LInet::SendCmd

#include " ltwrappr.h "

L_INT LInet::SendCmd (plRemoteComp, uCommand, uCommandID, pInetPacket=NULL)

LInet L_FAR * plRemoteComp;	/* instance of a remote computer */
CMDTYPE uCommand;	/* command type */
L_UINT uCommandID;	/* command id */
LlnetPacket * plnetPacket=NULL;	/* pointer to an LlnetPacket object */

Sends a command to a remote computer. This function is only available in the Internet toolkit.

Parameter	Description
plRemoteComp	Instance of the remote computer to which the command will be sent.
uCommand	The command to send. For a list of possible values, refer to CMDTYPE.
uCommandID	Command ID. Each command sent by a member of a connection should have a unique ID. Since a member of a connection may send several commands, this ID allows that member to identify when a specific command request has been completed.
plnetPacket	Pointer to an LlnetPacket object containing the parameters for the command. You can pass NULL if the command doesn't need any parameters.

Returns

SUCCESS	This function was successful.
< 1	An occurred. Refer to Return Codes.

Comments

The remote computer should respond by calling LInet::SendRsp in its LInet::CommandCallBack function.

To process responses to commands, a class must be derived from LInet and the LInet::ResponseCallBack member function must be overridden.

Some commands will send back only the command’s status (indicating whether the command succeeded or not). But some commands will send back additional information if the command succeeds. For example, responses to LInet::SendLoadCmd will send the bitmap ID while responses to LInet::SendCreateWinCmd will send the window identifier (which can be used to resize or close the window).

Required DLLs and Libraries

LTNET

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

See Also

Funtions:	LInet::SendRsp, LInet::CommandCallBack, LInet::ResponseCallBack, Class Members
Topics:	Sending Commands and Responses
	A Client Server Diagram: Sending Commands and Responses

Example

//This example sends a message to a remote connection to flip a bitmap
//It assumed that:
//1.  m_Inet is an object of the class LInet.
//2.  the network as been started (LInet::StartUp())
//3.  a connection has been established with a remote server (LInet::m_Inet.Connect())
//4.  GetNextCommandID() is a function that returns a unique command identifier
//5.  UpdateStatusbar() is a function that displays a message in the status bar
//6.  m_uWindowID is a window id that is received in the LInet::ResponseCallBack() as a result
//    of a call to m_Inet.SendCreateWinCmd()
//7.  m_uBitmapID is a bitmap id that is received in the LInet::ResponseCallBack() as a result
//    of a call to m_Inet.SendLoadCmd()
void CMainFrame::OnRemoteFlipbitmap()
{
      L_INT nRet;

      CMDTYPE CMD_FLIP;
      LInetPacket InetPacket(NULL, NULL, "%ud", m_uBitmapID);

      nRet = m_Inet.SendCmd(m_pInetRemoteServer, CMD_FLIP, GetNextCommandID(), &InetPacket);
      if(nRet != SUCCESS && nRet != ERROR_DATA_QUEUED)
      {
          UpdateStatusbar(TEXT("Error[%d]: OnRemoteFlipbitmap"), nRet);
      }
      else
      {
          UpdateStatusbar(TEXT("Success: OnRemoteFlipbitmap"), nRet);
      }

      //LInetPacket::~LInetPacket() destructor gets called here ...
}

//The CommandCallBack() is processed on the server
//To process the commands sent to the computer, you must:
//1. Derive a class from LInet
//2. Override the CommandCallBack member function
//
//Assume that
//1. m_Inet is an object of the class CMyNet (derived from LInet).
//2. the network as been started (LInet::StartUp())
//3. a connection has been established with a remote client
//4. UpdateStatusbar() displays a message in the status bar
//5. m_BitmapList maintains a list of LBitmapWindow objects
L_INT CMyNet::CommandCallBack(LInet L_FAR * plConnection,
                              CMDTYPE     uCommand,
                              L_UINT      uCommandID,
                              L_INT       nError,
                              L_UINT      uParams,
                              pPARAMETER  pParams,
                              L_UINT      uExtra,
                              L_CHAR L_FAR*pExtra)
{
     L_INT nStatus = ERROR_FEATURE_NOT_SUPPORTED;
     L_UINT          uBitmapID = (L_UINT)-1;

     CMainFrame *pMain;
     pMain = GETMAINFRAME;

     if(nError != SUCCESS)
         nStatus = ERROR_TRANSFER_ABORTED;
     else
         switch(uCommand)
         {
             case CMD_FLIP:
             {
                 uBitmapID = pParams->uiValue;

                  //Here you would look up the uBitmapID in a table to
                  //get the corresponding BitmapWindow object
                  //If the BitmapWindow object is valid, then flip the bitmap

                 /* Something like this
                 LBitmapWindow *pBitmapWindow = m_BitmapList[uBitmapID];
                 if (pBitmapWindow != NULL)
                 {
                     nStatus = pBitmapWindow->Flip();
                 }
                 */
             }
         break;
         }
     return pMain->m_Inet.SendRsp(
        plConnection,
        uCommand,
        uCommandID,
        NULL,
        nStatus
        );
}