Can a CIN that is in an infinite loop send data to labview without exiting?

Question

I have a C program that continuously queries a motor controller.  Right now that program is in a labview vi as a CIN.  The problem is that the CIN must exit before reporting the controller response to the labview vi.  This means I have to constantly run the CIN which opens, queries and closes the connection each time.  Is it possible to run the loop in the CIN itself so that the response buffer from the controller can be sent to the labview vi without exiting.  Are there variables types that can be passed from the CIN before completing the CIN? 

Answer 1

The controller is a Galil DMC4080 motor controller.  I am running Labview under Mandrake Linux.  I can connect and send commands to the controller using a C program.  I modified the C program as a CIN to pass the controller response to the Labview front panel.  Galil has a library of functions used for the controller commands.  LStrPrintf is the command I use to write the data to labview.  Currently I just run this CIN without a while loop and loop it in labview but I recieve an  error message  after  a 1000 executions, see: http://forums.ni.com/ni/board/message?board.id=170&message.id=270220
If interested here is the current code I am using with the infinite loop. 
#include "extcode.h"
#include "dmclnx.h"
#include "hosttype.h"
MgErr CINProperties(int32 prop, void *data);
MgErr CINRun(LStrHandle IPAddress, LStrHandle Command, LStrHandle Response,
        float64 *ErrorCode);
MgErr CINProperties(int32 prop, void *data)
    switch (prop) {
        case kCINIsReentrant:
            *(Bool32 *)data = TRUE;
            return noErr;
    return mgNotSupported;
MgErr CINRun(LStrHandle IPAddress, LStrHandle Command, LStrHandle Response,
        float64 *ErrorCode)
   float          rc = 0;          /* Return code */
   char           buffer[32] = ""; /* Response from controller */
   char           ip[20]=""; /* IP address of controller*/
   char           cmd[20]=""; /* Command to send to controller*/
   HANDLEDMC      hdmc = -1;       /* Handle to controller */
   CONTROLLERINFO controllerinfo;  /* Controller information structure */
   memset(&controllerinfo, '\0', sizeof(controllerinfo));
   controllerinfo.cbSize = sizeof(controllerinfo);
   controllerinfo.usModelID = MODEL_2100;
   controllerinfo.fControllerType = ControllerTypeEthernet;
   controllerinfo.ulTimeout = 1000;
   controllerinfo.ulDelay = 5;
   SPrintf(ip,"%H",IPAddress);
   strcpy(controllerinfo.hardwareinfo.socketinfo.szIPAddress, ip);
   controllerinfo.hardwareinfo.socketinfo.fProtocol = EthernetProtocolTCP;
   DMCInitLibrary();
   /* Open the connection */
   rc = DMCOpen(&controllerinfo, &hdmc);
   if (rc)
       *ErrorCode = rc;
       return noErr;
      while (1)
          SPrintf(cmd,"%H",Command);
          rc = DMCCommand(hdmc, cmd, buffer, sizeof(buffer));
          if (rc)
              *ErrorCode = rc;
              return noErr;
              break;
          else
              LStrPrintf(Response,buffer);
   rc = DMCClose(hdmc);
   if (rc)
      *ErrorCode = rc;
      return noErr;
   *ErrorCode = rc;
   return noErr;