message.cpp

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#include "examples.h"

#include <iostream> //std::cout
#include <string.h>
using namespace std;

GReturn message(GCon g) 
{
  char buf[G_SMALL_BUFFER]; //traffic buffer
  cout << "***************************************************************\n";
  cout << "Example GMessage() usage\n";
  cout << "***************************************************************\n";

  e(GCmd(g, "TR0")); // Turn off trace
  
  //This program will force one message to appear as two separate packets.
  e(GProgramDownload(g, 
    "MG \"HELLO \" {N}\r"
    "MG \"WORLD \"\r"
    "EN", 0));
  e(GCmd(g, "XQ")); //Begins execution of program on controller

  int rc = 0;
  char message[G_SMALL_BUFFER];
  int b = 0; //iterator for buf
  int m = 0; //iterator for message

  // It is important to note that a message can be too large to read in one
  // GMessage() call. Keep calling GMessage() while there are no errors to 
  // get the full message.

  //While still receiving messages
  while ((rc = GMessage(g, buf, G_SMALL_BUFFER)) == G_NO_ERROR)
  {
    b = 0; //reset buffer index

    while (buf[b] != '\0') //While message characters are in the buffer
    {
      message[m] = buf[b]; //Copy chars from buffer to message

      //If the message ends in "\r\n" its ready to be terminated
      if (m > 0 && message[m] == '\n' && message[m - 1] == '\r')
      {
        message[m + 1] = '\0'; //Null terminate the message
        cout << '<' << message << ">\n";
        m = 0;  //Reset message index
      }
      else
      {
        m++; //Increment message index
      }

      b++; //Increment buf index
    }
  }
  
  //Downloads program to the controller
  e(GCmd(g, "TR1")); // Turn on trace
  e(GProgramDownload(g, "i=0\r"
    "#A\r"
    "MGi\r"
    "i=i+1\r"
    "WT100\r"
    "JP#A,i<1\r"
    "i=i/0\r"
    "EN", 0));
  e(GCmd(g, "XQ")); //Begins execution of program on controller

  m = 0; //Reset message buffer

  // Lines returned by GMessage() can be one of three types:
  // 1) Standard Lines begin with a space (" ")
  // 2) Crashed code begins with a question mark ("?")
  // 3) Trace Lines begin with a line number ("1,6,15...")

  //While still receiving messages
  while ((rc = GMessage(g, buf, G_SMALL_BUFFER)) == G_NO_ERROR)
  {
    b = 0; //reset buf index

    while (buf[b] != '\0') //While message characters are in the buffer
    {
      message[m] = buf[b]; //Copy chars from buffer to message

      //If the message ends in "\r\n" its ready to be terminated
      if (m > 0 && message[m] == '\n' && message[m - 1] == '\r')
      {
        message[m + 1] = '\0'; //Null terminate the message
        
        if (message[0] == ' ') //Standard Lines begin with a space (" ")
          cout << "Standard Line: ";
        else if (message[0] == '?') //Crashed code begins with a question mark ("?")
          cout << "Crashed Code: ";
        else //Trace Lines begin with a line number ("1,6,15...")
          cout << "Trace Line: ";
        
        cout << message;

        m = 0;  //Reset message index
      }
      else
      {
        m++; //Increment message index
      }

      b++; //Increment buf index
    }
  }

  // If no communication has been made to gcaps for 10 minutes the connection
  // will expire. This can be prevented by periodically sending the GUtility()
  // Keep Alive command
  e(GUtility(g, G_UTIL_GCAPS_KEEPALIVE, NULL, NULL));

  return  GALIL_EXAMPLE_OK;
}