x_nonblocking.cpp

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#include "x_examples.h"
#include <iomanip> //hex printing
 
int cur = 0;
char chars[] = { '|', '\\', '-','/'};
//simple progress indicator.
void progress()
{
  cout << chars[cur] << '\r';
  cout.flush();
  ++cur %= 4;
}
 
 
//demonstrates non-blocking calls of GMessage(), GInterrupt(), and GRecord().
int x_nonblocking(GCon g)
{
 
  // *** we assume -s ALL was passed to Open. ***
  GReturn rc;
  char buf[1024]; //read buffer
  
  cout << "\n************************************************************************\n";
  cout << "Example GMessage non-blocking usage\n";
  cout << "************************************************************************\n";
  
  x_e(GProgramDownload(g, "WT2000;MG TIME;EN", 0)); //wait 2 seconds, then print message
  x_e(GCmd(g, "XQ"));
 
  x_e(GTimeout(g, 0)); //set timeout to zero for non-blocking read
  
  for (int i = 0;
    (rc = GMessage(g, buf, sizeof(buf))) == G_GCLIB_NON_BLOCKING_READ_EMPTY; 
    i++)
  {
    x_e(GCmd(g, "MGTIME")); //do something useful here...
    progress(); //and here
  }
  
  x_e(rc); //verify the return code
  x_e(GTimeout(g, -1)); //put the timeout back to the GOpen() setting
  cout << buf << '\n'; //print the message
 
  cout << "\n************************************************************************\n";
  cout << "Example GInterrupt non-blocking usage\n";
  cout << "************************************************************************\n";
  x_e(GProgramDownload(g, "WT2000;UI1;EN", 0)); //wait 2 seconds, then fire interrupt
  x_e(GCmd(g, "XQ")); //start code
 
  GStatus byte = 0; //variable for the interrupt byte
  x_e(GTimeout(g, 0)); //set timeout to zero for non-blocking read
 
  while ((rc = GInterrupt(g, &byte)) == G_GCLIB_NON_BLOCKING_READ_EMPTY)
  {
    x_e(GCmd(g, "MGTIME")); //do something useful here...
    progress(); //and here
  }
  x_e(rc); //verify the return code
  x_e(GTimeout(g, -1)); //put the timeout back to the GOpen() setting
  cout << " " << hex << uppercase << (int) byte << dec << '\n'; //print the byte in hex
 
 
  cout << "\n************************************************************************\n";
  cout << "Example GRecord non-blocking usage\n";
  cout << "************************************************************************\n";
  
  GDataRecord dr;
  x_e(GRecordRate(g, 0)); //turn off data record
  x_e(GTimeout(g, 0)); //set timeout to zero for non-blocking read
  GRecord(g, &dr, G_DR); //throw away a waiting record
  x_e(GTimeout(g, -1)); //put the timeout back to the GOpen() setting
  x_e(GRecordRate(g, 2000)); //turn on data record
  x_e(GTimeout(g, 0)); //set timeout to zero for non-blocking read
  while ((rc = GRecord(g, &dr, G_DR)) == G_GCLIB_NON_BLOCKING_READ_EMPTY)
  {
    x_e(GCmd(g, "MGTIME")); //do something useful here...
    progress(); //and here
  }
  x_e(rc); //verify the return code
  x_e(GTimeout(g, -1)); //put the timeout back to the GOpen() setting
  x_e(GRecordRate(g, 0)); //turn off data record
  cout << " " << dr.dmc4000.sample_number << '\n';
 
  return GALIL_EXAMPLE_OK;
}