func finalizeMsg(datap *[]byte) error {
hdrp := (*reflect.SliceHeader)(unsafe.Pointer(datap))
if rc, err := C.nn_freemsg(unsafe.Pointer(hdrp.Data)); rc != 0 {
return nnError(err)
}
return nil
}
// Recv receives a message from the socket. The flags argument can be zero or
// DontWait.
func (s *Socket) Recv(flags int) ([]byte, error) {
var err error
var buf unsafe.Pointer
var length C.int
if length, err = C.nn_recv(s.socket, unsafe.Pointer(&buf), nn_msg, C.int(flags)); length < 0 {
return nil, nnError(err)
}
// TODO why is the latter variant faster than the zero copy variant?
zeroCopy := true
if zeroCopy {
capacity := int(length)
header := &reflect.SliceHeader{
Data: uintptr(buf),
Len: capacity,
Cap: capacity,
}
data := *((*[]byte)(unsafe.Pointer(header)))
runtime.SetFinalizer(&data, finalizeMsg)
return data, nil
} else {
data := C.GoBytes(buf, length)
if rc, err := C.nn_freemsg(buf); rc != 0 {
return data, nnError(err)
}
return data, nil
}
}