Poll events from input devices using libevdev

gistfile1.txt

#include <libevdev-1.0/libevdev/libevdev.h>
#include <filesystem>
#include <iostream>
#include <vector>
#include <fcntl.h>

struct InputDevice
{
  int fileDescriptor = 0;
  libevdev* device = nullptr;
};

int main()
{
  std::vector<InputDevice> devices;

  const std::string base = "/dev/input/event";
  for (auto const& entry : std::filesystem::directory_iterator{"/dev/input"}) {
    auto path = entry.path().string();
    if (path.starts_with(base)) {
      int i = std::stoi(path.substr(base.length()));
      if (i + 1 > devices.size()) {
        devices.resize(i + 1);
      }

      devices[i].fileDescriptor = open(path.c_str(), O_RDONLY | O_NONBLOCK);

      if (libevdev_new_from_fd(devices[i].fileDescriptor, &devices[i].device) < 0) {
        std::cerr << "Failed to init libevdev\n";
        return 1;
      }

      std::cout << "Input device: " << libevdev_get_name(devices[i].device) << "\n";
    }
  }

  while (1) {
    for (size_t i = 0; i < devices.size(); ++i) {
      auto& device = devices[i];

      input_event event;
      auto result = libevdev_next_event(device.device, LIBEVDEV_READ_FLAG_NORMAL, &event);

      if (result == LIBEVDEV_READ_STATUS_SUCCESS) {
        std::cout << i << ": " << "Event: " << libevdev_event_type_get_name(event.type) << " "
          << libevdev_event_code_get_name(event.type, event.code) << " " << event.value << "\n";
      }
    }
  }

  return 0;
}