//   - gvisor.dev/gvisor
//   - github.com/sagernet/gvisor
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname sync_runtime_Semrelease sync.runtime_Semrelease
func sync_runtime_Semrelease(addr *uint32, handoff bool, skipframes int) {
	semrelease1(addr, handoff, skipframes)
}

//go:linkname sync_runtime_SemacquireMutex sync.runtime_SemacquireMutex

	// Poller may want to unregister fd in readiness notification mechanism,
	// so this must be executed before CloseFunc.
	fd.pd.close()

	err := fd.SysFile.destroy(fd.Sysfd)

	fd.Sysfd = -1
	runtime_Semrelease(&fd.csema)
	return err
}

// Close closes the FD. The underlying file descriptor is closed by the
// destroy method when there are no remaining references.
func (fd *FD) Close() error {

	case kindNet:
		// The net package uses the CloseFunc variable for testing.
		err = CloseFunc(fd.Sysfd)
	default:
		err = syscall.CloseHandle(fd.Sysfd)
	}
	fd.Sysfd = syscall.InvalidHandle
	runtime_Semrelease(&fd.csema)
	return err
}

// Close closes the FD. The underlying file descriptor is closed by
// the destroy method when there are no remaining references.
func (fd *FD) Close() error {