Check if device path exists on Windows

devpath_check.cc

#include <Windows.h>
#include <stdio.h>
#include <string>

using std::string;

void testdev(string devname) {
  string path = "\\\\?\\Global\\GLOBALROOT\\Device\\" + devname;

  printf("----------------- %s\n", devname.c_str());
  HANDLE h = CreateFile(
    path.c_str(),
    GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);

  DWORD error = GetLastError();

  printf("Handle: %p, Error: %u\n", h, (unsigned)error);

  if (h != INVALID_HANDLE_VALUE ||
      (h == INVALID_HANDLE_VALUE && error == 5)) {
    puts("Found the device!");
  } else {
    puts("Device not present");
  }

  if (h != INVALID_HANDLE_VALUE) {
    CloseHandle(h);
  }

}

int main(void) {
  testdev("Beep");  // Everyone should have access.
  testdev("PartmgrControl"); // Only admin has access.
  testdev("IDontExist"); // Guess.


  return 0;
}