Man pages sections > man3 > Obj

Obj - Operations on internal representations of values.

Obj(3o) OCamldoc Obj(3o)

NAME

Obj - Operations on internal representations of values.

Module

Module Obj

Documentation

Module Obj
: sig end
 
 
Operations on internal representations of values.
 
Not for the casual user.
 
 
 
 
 
type t
 
 
 
 
 
val repr : 'a -> t
 
 
 
 
val obj : t -> 'a
 
 
 
 
val magic : 'a -> 'b
 
 
 
 
val is_block : t -> bool
 
 
 
 
val is_int : t -> bool
 
 
 
 
val tag : t -> int
 
 
 
 
val size : t -> int
 
 
 
 
val reachable_words : t -> int
 
Computes the total size (in words, including the headers) of all heap blocks accessible from the argument. Statically allocated blocks are excluded.
 
@Since 4.04
 
 
 
val field : t -> int -> t
 
 
 
 
val set_field : t -> int -> t -> unit
 
When using flambda:
 
 
set_field MUST NOT be called on immutable blocks. (Blocks allocated in C stubs, or with new_block below, are always considered mutable.)
 
The same goes for set_double_field and set_tag . However, for set_tag , in the case of immutable blocks where the middle-end optimizers never see code that discriminates on their tag (for example records), the operation should be safe. Such uses are nonetheless discouraged.
 
For experts only: set_field et al can be made safe by first wrapping the block in Sys.opaque_identity , so any information about its contents will not be propagated.
 
 
 
val set_tag : t -> int -> unit
 
 
 
 
val double_field : t -> int -> float
 
 
 
 
val set_double_field : t -> int -> float -> unit
 
 
 
 
val new_block : int -> int -> t
 
 
 
 
val dup : t -> t
 
 
 
 
val truncate : t -> int -> unit
 
 
 
 
val add_offset : t -> Int32.t -> t
 
 
 
 
val first_non_constant_constructor_tag : int
 
 
 
 
val last_non_constant_constructor_tag : int
 
 
 
 
val lazy_tag : int
 
 
 
 
val closure_tag : int
 
 
 
 
val object_tag : int
 
 
 
 
val infix_tag : int
 
 
 
 
val forward_tag : int
 
 
 
 
val no_scan_tag : int
 
 
 
 
val abstract_tag : int
 
 
 
 
val string_tag : int
 
 
 
 
val double_tag : int
 
 
 
 
val double_array_tag : int
 
 
 
 
val custom_tag : int
 
 
 
 
val final_tag : int
 
 
 
 
val int_tag : int
 
 
 
 
val out_of_heap_tag : int
 
 
 
 
val unaligned_tag : int
 
 
 
 
val extension_constructor : 'a -> extension_constructor
 
 
 
 
val extension_name : extension_constructor -> string
 
 
 
 
val extension_id : extension_constructor -> int
 
 
 
 
=== The following two functions are deprecated. Use module Marshal instead. ===
 
val marshal : t -> bytes
 
 
 
 
val unmarshal : bytes -> int -> t * int
 
 
 
module Ephemeron : sig end
 
 
 
 
source: 2017-10-04