uwt 0.0.2 · OCaml Package

type t

include module type of Handle with type t := t

val close : t -> Int_result.unit

Handles are closed automatically, if they are not longer referenced from the OCaml heap. Nevertheless, you should nearly always close them with close, because:

if they wrap a file descriptor, you will sooner or later run out of file descriptors. The OCaml garbage collector doesn't give any guarantee, when orphaned memory blocks are removed.

you might have registered some repeatedly called action (e.g. timeout, read_start,...), that prevent that all references get removed from the OCaml heap.

However, it's safe to write code in this manner:

let s = Uwt.Tcp.init () in
let c = Uwt.Tcp.init () in
Uwt.Tcp.nodelay s false;
Uwt.Tcp.simultaneous_accepts true;
if foobar () then (* no file descriptor yet assigned, no need to worry
                     about exceptions inside foobar,... *)
  Lwt.return_unit (* no need to close *)
else
  ...

If you want - for whatever reason - keep a file descriptor open for the whole lifetime of your process, remember to keep a reference to its handle.

val close_noerr : t -> unit

val close_wait : t -> unit Lwt.t

Prefer close or close_noerr to close_wait. close or close_noerr return immediately (there are no useful error messages, beside perhaps a notice, that you've already closed that handle).

close_wait is only useful, if you intend to wait until all concurrent write and read threads related to this handle are canceled.

val is_active : t -> bool

val ref' : t -> unit

val unref : t -> unit

val has_ref : t -> bool

val to_handle : t -> Handle.t

val is_readable : t -> bool

val is_writable : t -> bool

val read_start : t -> cb:(Bytes.t result -> unit) -> Int_result.unit

val read_start_exn : t -> cb:(Bytes.t result -> unit) -> unit

val read_stop : t -> Int_result.unit

val read_stop_exn : t -> unit

val read : ?pos:int -> ?len:int -> t -> buf:bytes -> int Lwt.t

There is currently no uv_read function in libuv, just read_start and * read_stop. * This is a wrapper for your convenience. It calls read_stop internally, if * you don't continue with reading immediately. Zero result indicates EOF. * * There are currently plans to add uv_read and uv_try_read to libuv * itself. If these changes got merged, Stream.read will wrap them - * even if there will be small semantic differences.

val read_ba : ?pos:int -> ?len:int -> t -> buf:buf -> int Lwt.t

val write_queue_size : t -> int

val try_write : ?pos:int -> ?len:int -> t -> buf:bytes -> Int_result.int

val try_write_ba : ?pos:int -> ?len:int -> t -> buf:buf -> Int_result.int

val try_write_string : 
  ?pos:int ->
  ?len:int ->
  t ->
  buf:string ->
  Int_result.int

val write : ?pos:int -> ?len:int -> t -> buf:bytes -> unit Lwt.t

val write_string : ?pos:int -> ?len:int -> t -> buf:string -> unit Lwt.t

val write_ba : ?pos:int -> ?len:int -> t -> buf:buf -> unit Lwt.t

val write_raw : ?pos:int -> ?len:int -> t -> buf:bytes -> unit Lwt.t

write is eager. If len is not very large, it first calls try_write internally to check if it can return immediately (without the overhead of creating a sleeping thread and waking it up later). If it can't write everything instantly, it will call write_raw internally. write_raw is exposed here mainly in order to write unit tests for it. But you can also use it, if you your buf is very large or you know for another reason, that try_write will fail.

val write_raw_string : ?pos:int -> ?len:int -> t -> buf:string -> unit Lwt.t

val write_raw_ba : ?pos:int -> ?len:int -> t -> buf:buf -> unit Lwt.t

val write2 : ?pos:int -> ?len:int -> buf:bytes -> send:t -> t -> unit Lwt.t

val write2_ba : ?pos:int -> ?len:int -> buf:buf -> send:t -> t -> unit Lwt.t

val write2_string : 
  ?pos:int ->
  ?len:int ->
  buf:string ->
  send:t ->
  t ->
  unit Lwt.t

val listen : 
  t ->
  max:int ->
  cb:(t -> Int_result.unit -> unit) ->
  Int_result.unit

val listen_exn : t -> max:int -> cb:(t -> Int_result.unit -> unit) -> unit

val accept_raw : server:t -> client:t -> Int_result.unit

val accept_raw_exn : server:t -> client:t -> unit

val shutdown : t -> unit Lwt.t

package uwt