Thread: A small Debug routine

Hi,
following is a small debugging routine embedded in some working sample source code provided by a hardware supplier. I am just going through their sample source code to get a better understanding of how their API works. However, I just can't make sense of how the parameters of DEBUG(x, outp) are being passed to dbg_p (char i, char *fmt, ...). What does "..." in dbg_p (char i, char *fmt, ...) mean?

Would really appreciate if someone can enlighten me.

Thanks in advance.

Code:

/* defines for debugging */
#define DEBUG_OFF           99
#define DEBUG_BASIC         03 
#define DEBUG_ADV           02
#define DEBUG_EXP           01

static int can_debug = DEBUG_EXP;

// debug version
#ifdef _DEBUG

    #define DEBUG(x, outp)        ( dbg_p(x, outp ) )

    _inline void dbg_p (char i, char *fmt, ...)
    {
      char tmp[100];
      if (i>=can_debug){

        sprintf (tmp, "xlCANcontrol: %s", fmt);

        OutputDebugString (tmp);
      }
    } 
    
// release version.
#else
    #define DEBUG(x, outp)     
#endif

Following is a portion of the main routine that calls the debugging routine:

Code:

XLstatus CCANFunctions::canGetChannelMask()
{
  XLstatus        xlStatus = XL_ERROR;
  char            tmp[100];

  // default values
  unsigned int  hwType     = 0;
  unsigned int  hwIndex    = 0;
  unsigned int  hwChannel  = 0;
  unsigned int  appChannel = 0;
  unsigned int  busType    = XL_BUS_TYPE_CAN;   
  unsigned int  i; 
 
  XLdriverConfig  xlDrvConfig;

   //check for hardware:
  xlStatus = xlGetDriverConfig(&xlDrvConfig);
  if (xlStatus) return xlStatus;
  
  // we check only if there is an application registered or not.
  xlStatus = xlGetApplConfig("xlCANcontrol", CHAN01, &hwType, &hwIndex, &hwChannel, busType); 
 
  // Set the params into registry (default values...!)
  if (xlStatus) {
    DEBUG(DEBUG_ADV,"set in VHWConf");

    for (i=0; i < xlDrvConfig.channelCount; i++) {

      sprintf (tmp, "hwType: %d, bustype: %d, hwChannel: %d, cap: 0x%x", 
        xlDrvConfig.channel[i].hwType, 
        xlDrvConfig.channel[i].connectedBusType,
        xlDrvConfig.channel[i].hwChannel,
        xlDrvConfig.channel[i].channelBusCapabilities);
      DEBUG(DEBUG_ADV,tmp);

      // we search not the first CAN cabs
      if ( (xlDrvConfig.channel[i].channelBusCapabilities & XL_BUS_ACTIVE_CAP_CAN) && (appChannel < 2) ) {

        hwType    = xlDrvConfig.channel[i].hwType;
        hwIndex   = xlDrvConfig.channel[i].hwIndex;
        hwChannel = xlDrvConfig.channel[i].hwChannel;

.
.
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