Module Stdlib.Nativeint

Processor-native integers.

This module provides operations on the type nativeint of signed 32-bit integers (on 32-bit platforms) or signed 64-bit integers (on 64-bit platforms). This integer type has exactly the same width as that of a pointer type in the C compiler. All arithmetic operations over nativeint are taken modulo 232 or 264 depending on the word size of the architecture.

Performance notice: values of type nativeint occupy more memory space than values of type int, and arithmetic operations on nativeint are generally slower than those on int. Use nativeint only when the application requires the extra bit of precision over the int type.

Literals for native integers are suffixed by n:

let zero: nativeint = 0n
let one: nativeint = 1n
let m_one: nativeint = -1n
val zero : nativeint

The native integer 0.

val one : nativeint

The native integer 1.

val minus_one : nativeint

The native integer -1.

val neg : nativeint -> nativeint

Unary negation.

val add : nativeint -> nativeint -> nativeint

Addition.

val sub : nativeint -> nativeint -> nativeint

Subtraction.

val mul : nativeint -> nativeint -> nativeint

Multiplication.

val div : nativeint -> nativeint -> nativeint

Integer division. This division rounds the real quotient of its arguments towards zero, as specified for Stdlib.(/).

val unsigned_div : nativeint -> nativeint -> nativeint

Same as div, except that arguments and result are interpreted as unsigned native integers.

  • since 4.08
val rem : nativeint -> nativeint -> nativeint

Integer remainder. If y is not zero, the result of Nativeint.rem x y satisfies the following properties: Nativeint.zero <= Nativeint.rem x y < Nativeint.abs y and x = Nativeint.add (Nativeint.mul (Nativeint.div x y) y) (Nativeint.rem x y). If y = 0, Nativeint.rem x y raises Division_by_zero.

val unsigned_rem : nativeint -> nativeint -> nativeint

Same as rem, except that arguments and result are interpreted as unsigned native integers.

  • since 4.08
val succ : nativeint -> nativeint

Successor. Nativeint.succ x is Nativeint.add x Nativeint.one.

val pred : nativeint -> nativeint

Predecessor. Nativeint.pred x is Nativeint.sub x Nativeint.one.

val abs : nativeint -> nativeint

abs x is the absolute value of x. On min_int this is min_int itself and thus remains negative.

val size : int

The size in bits of a native integer. This is equal to 32 on a 32-bit platform and to 64 on a 64-bit platform.

val max_int : nativeint

The greatest representable native integer, either 231 - 1 on a 32-bit platform, or 263 - 1 on a 64-bit platform.

val min_int : nativeint

The smallest representable native integer, either -231 on a 32-bit platform, or -263 on a 64-bit platform.

val logand : nativeint -> nativeint -> nativeint

Bitwise logical and.

val logor : nativeint -> nativeint -> nativeint

Bitwise logical or.

val logxor : nativeint -> nativeint -> nativeint

Bitwise logical exclusive or.

val lognot : nativeint -> nativeint

Bitwise logical negation.

val shift_left : nativeint -> int -> nativeint

Nativeint.shift_left x y shifts x to the left by y bits. The result is unspecified if y < 0 or y >= bitsize, where bitsize is 32 on a 32-bit platform and 64 on a 64-bit platform.

val shift_right : nativeint -> int -> nativeint

Nativeint.shift_right x y shifts x to the right by y bits. This is an arithmetic shift: the sign bit of x is replicated and inserted in the vacated bits. The result is unspecified if y < 0 or y >= bitsize.

val shift_right_logical : nativeint -> int -> nativeint

Nativeint.shift_right_logical x y shifts x to the right by y bits. This is a logical shift: zeroes are inserted in the vacated bits regardless of the sign of x. The result is unspecified if y < 0 or y >= bitsize.

val of_int : int -> nativeint

Convert the given integer (type int) to a native integer (type nativeint).

val to_int : nativeint -> int

Convert the given native integer (type nativeint) to an integer (type int). The high-order bit is lost during the conversion.

val unsigned_to_int : nativeint -> int option

Same as to_int, but interprets the argument as an unsigned integer. Returns None if the unsigned value of the argument cannot fit into an int.

  • since 4.08
val of_float : float -> nativeint

Convert the given floating-point number to a native integer, discarding the fractional part (truncate towards 0). If the truncated floating-point number is outside the range [Nativeint.min_int, Nativeint.max_int], no exception is raised, and an unspecified, platform-dependent integer is returned.

val to_float : nativeint -> float

Convert the given native integer to a floating-point number.

val of_int32 : int32 -> nativeint

Convert the given 32-bit integer (type int32) to a native integer.

val to_int32 : nativeint -> int32

Convert the given native integer to a 32-bit integer (type int32). On 64-bit platforms, the 64-bit native integer is taken modulo 232, i.e. the top 32 bits are lost. On 32-bit platforms, the conversion is exact.

val of_string : string -> nativeint

Convert the given string to a native integer. The string is read in decimal (by default, or if the string begins with 0u) or in hexadecimal, octal or binary if the string begins with 0x, 0o or 0b respectively.

The 0u prefix reads the input as an unsigned integer in the range [0, 2*Nativeint.max_int+1]. If the input exceeds Nativeint.max_int it is converted to the signed integer Int64.min_int + input - Nativeint.max_int - 1.

  • raises Failure

    if the given string is not a valid representation of an integer, or if the integer represented exceeds the range of integers representable in type nativeint.

val of_string_opt : string -> nativeint option

Same as of_string, but return None instead of raising.

  • since 4.05
val to_string : nativeint -> string

Return the string representation of its argument, in decimal.

type t = nativeint

An alias for the type of native integers.

val compare : t -> t -> int

The comparison function for native integers, with the same specification as Stdlib.compare. Along with the type t, this function compare allows the module Nativeint to be passed as argument to the functors Set.Make and Map.Make.

val unsigned_compare : t -> t -> int

Same as compare, except that arguments are interpreted as unsigned native integers.

  • since 4.08
val equal : t -> t -> bool

The equal function for native ints.

  • since 4.03
val min : t -> t -> t

Return the smaller of the two arguments.

  • since 4.13
val max : t -> t -> t

Return the greater of the two arguments.

  • since 4.13
val seeded_hash : int -> t -> int

A seeded hash function for native ints, with the same output value as Hashtbl.seeded_hash. This function allows this module to be passed as argument to the functor Hashtbl.MakeSeeded.

  • since 5.1
val hash : t -> int

An unseeded hash function for native ints, with the same output value as Hashtbl.hash. This function allows this module to be passed as argument to the functor Hashtbl.Make.

  • since 5.1