test_usb.cpp

#include <iostream>
#include <libusb.h>
using namespace std;

void printdev(libusb_device *dev); //prototype of the function

int main() {
  libusb_device **devs; //pointer to pointer of device, used to retrieve a list of devices
  libusb_context *ctx = NULL; //a libusb session
  int r; //for return values
  ssize_t cnt; //holding number of devices in list
  r = libusb_init(&ctx); //initialize a library session
  if(r < 0) {
    cout<<"Init Error "<<r<<endl; //there was an error
    return 1;
  }
  libusb_set_debug(ctx, 3); //set verbosity level to 3, as suggested in the documentation
  cnt = libusb_get_device_list(ctx, &devs); //get the list of devices
  if(cnt < 0) {
    cout<<"Get Device Error"<<endl; //there was an error
  }
  cout<<cnt<<" Devices in list."<<endl; //print total number of usb devices
  ssize_t i; //for iterating through the list
  for(i = 0; i < cnt; i++) {
    printdev(devs[i]); //print specs of this device
  }
  libusb_free_device_list(devs, 1); //free the list, unref the devices in it
  libusb_exit(ctx); //close the session
  return 0;
}

void printdev(libusb_device *dev) {
  libusb_device_descriptor desc;
  int r = libusb_get_device_descriptor(dev, &desc);
  if (r < 0) {
    cout<<"failed to get device descriptor"<<endl;
    return;
  }
  cout<<"Number of possible configurations: "<<(int)desc.bNumConfigurations<<"  ";
  cout<<"Device Class: "<<(int)desc.bDeviceClass<<"  ";
  cout<<"VendorID: "<<desc.idVendor<<"  ";
  cout<<"ProductID: "<<desc.idProduct<<endl;
  libusb_config_descriptor *config;
  libusb_get_config_descriptor(dev, 0, &config);
  cout<<"Interfaces: "<<(int)config->bNumInterfaces<<" ||| ";
  const libusb_interface *inter;
  const libusb_interface_descriptor *interdesc;
  const libusb_endpoint_descriptor *epdesc;
  for(int i=0; i<(int)config->bNumInterfaces; i++) {
    inter = &config->interface[i];
    cout<<"Number of alternate settings: "<<inter->num_altsetting<<" | ";
    for(int j=0; j<inter->num_altsetting; j++) {
      interdesc = &inter->altsetting[j];
      cout<<"Interface Number: "<<(int)interdesc->bInterfaceNumber<<" | ";
      cout<<"Number of endpoints: "<<(int)interdesc->bNumEndpoints<<" | ";
      for(int k=0; k<(int)interdesc->bNumEndpoints; k++) {
        epdesc = &interdesc->endpoint[k];
        cout<<"Descriptor Type: "<<(int)epdesc->bDescriptorType<<" | ";
        cout<<"EP Address: "<<(int)epdesc->bEndpointAddress<<" | ";
      }
    }
  }
  cout<<endl<<endl<<endl;
  libusb_free_config_descriptor(config);
}