how-to/c/listChannels.c

This example shows how to show information about all enumerated CANlib channels. See Library Initialization and Identifying Devices and Channels for more information.

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#include <stdint.h>
#include <stdio.h>
#include "canlib.h"

static void check(char* id, canStatus stat);
void show_channel_info(int channel_no);

// Find out how many channels that exists and loop over them
void list_channels(void)
{
  char driverName[256];
  int chanCount = 0;
  canStatus stat;
  int i;

  stat = canGetNumberOfChannels(&chanCount);
  check("canGetNumberOfChannels", stat);

  printf("Found %d channel(s).\n", chanCount);
  for (i = 0; i < chanCount; i++) {
    show_channel_info(i);
  }
} // list_channels

// Print status message if stat contains an error code
static void check(char* id, canStatus stat)
{
  if (stat != canOK) {
    char buf[50];
    buf[0] = '\0';
    // Retreive informational text about the status code
    canGetErrorText(stat, buf, sizeof(buf));
    printf("%s: failed, stat=%d (%s)\n", id, (int)stat, buf);
  }
} // check

void show_channel_info(int channel_no)
{
  canStatus stat;
  char name[256];
  char driverName[256];
  char custChanName[40];
  unsigned int ean[2], fw[2], serial[2];
  unsigned int chan_no_on_card;


  memset(name, 0, sizeof(name));
  memset(custChanName, 0, sizeof(custChanName));
  memset(ean, 0, sizeof(ean));
  memset(fw, 0, sizeof(fw));
  memset(serial, 0, sizeof(serial));

  stat = canGetChannelData(channel_no, canCHANNELDATA_DEVDESCR_ASCII, &name, sizeof(name));
  check("canGetChannelData: DEVDESCR_ASCII", stat);

  stat = canGetChannelData(channel_no, canCHANNELDATA_CARD_UPC_NO, &ean, sizeof(ean));
  check("canGetChannelData: CARD_UPC_NO", stat);

  stat = canGetChannelData(channel_no, canCHANNELDATA_CARD_SERIAL_NO, &serial, sizeof(serial));
  check("canGetChannelData: CARD_SERIAL_NO", stat);

  stat = canGetChannelData(channel_no, canCHANNELDATA_CARD_FIRMWARE_REV, &fw, sizeof(fw));
  check("canGetChannelData: CARD_FIRMWARE_REV", stat);

  stat = canGetChannelData(channel_no, canCHANNELDATA_CHAN_NO_ON_CARD,
                           &chan_no_on_card, sizeof(chan_no_on_card));
  check("canGetChannelData: canCHANNELDATA_CHAN_NO_ON_CARD", stat);

  canGetChannelData(channel_no, canCHANNELDATA_CUST_CHANNEL_NAME,
                    custChanName, sizeof(custChanName));

  printf("ch %2.1d: %-22s\t%x-%05x-%05x-%x, s/n %u, v%u.%u.%u :%d \"%s\"\n",
         channel_no, name,
         (ean[1] >> 12), ((ean[1] & 0xfff) << 8) | ((ean[0] >> 24) & 0xff),
         (ean[0] >> 4) & 0xfffff, (ean[0] & 0x0f),
         serial[0],
         fw[1] >> 16, fw[1] & 0xffff, fw[0] & 0xffff,
         chan_no_on_card, custChanName);
} // list_channel