import "syscall"

func PidFDSendSignal(pidfd uintptr, s syscall.Signal) error {
	_, _, errno := syscall.Syscall(pidfdSendSignalTrap, pidfd, uintptr(s), 0)
	if errno != 0 {
		return errno
	}
	return nil
}

func PidFDOpen(pid, flags int) (uintptr, error) {
	pidfd, _, errno := syscall.Syscall(pidfdOpenTrap, uintptr(pid), uintptr(flags), 0)
	if errno != 0 {
		return ^uintptr(0), errno
	}
	return uintptr(pidfd), nil

	if !pidfdWorks() {
		return 0, false
	}

	return uintptr(*sysAttr.PidFD), true
}

func pidfdFind(pid int) (uintptr, error) {
	if !pidfdWorks() {
		return 0, syscall.ENOSYS
	}

	h, err := unix.PidFDOpen(pid, 0)
	if err != nil {
		return 0, convertESRCH(err)
	}
	return h, nil
}

// _P_PIDFD is used as idtype argument to waitid syscall.
const _P_PIDFD = 3