# enum Atomic::Ordering

##
Overview

Specifies how memory accesses, including non atomic, are to be reordered around atomics. Follows the C/C++ semantics: https://en.cppreference.com/w/c/atomic/memory_order.

By default atomics use the sequentially consistent ordering, which has the strongest guarantees. If all you need is to increment a counter, a relaxed ordering may be enough. If you need to synchronize access to other memory (e.g. locks) you may try the acquire/release semantics that may be faster on some architectures (e.g. X86) but remember that an acquire must be paired with a release for the ordering to be guaranteed.

The code generation always enforces the selected memory order, even on weak CPU architectures (e.g. ARM32), with the exception of the Relaxed memory order where only the operation itself is atomic.

##
Defined in:

atomic.cr

##
Enum Members

Relaxed = `2`
Acquire = `4`
Release = `5`
AcquireRelease = `6`
SequentiallyConsistent = `7`

##
Instance Method Summary

- #acquire?
- #acquire_release?
- #relaxed?
- #release?
- #sequentially_consistent?

### Instance methods inherited from struct `Enum`

&(other : self) : self &, +(other : Int) : self +, -(other : Int) : self -, <=>(other : self) <=>, ==(other : self)
==(other) ==, ^(other : self) : self ^, |(other : self) : self |, ~ : self ~, clone clone, each(& : self -> ) each, hash(hasher) hash, includes?(other : self) : Bool includes?, inspect(io : IO) : Nil inspect, to_f32 : Float32 to_f32, to_f32! : Float32 to_f32!, to_f64 : Float64 to_f64, to_f64! : Float64 to_f64!, to_i : Int32 to_i, to_i128 : Int128 to_i128, to_i128! : Int128 to_i128!, to_i16 : Int16 to_i16, to_i16! : Int16 to_i16!, to_i32 : Int32 to_i32, to_i32! : Int32 to_i32!, to_i64 : Int64 to_i64, to_i64! : Int64 to_i64!, to_i8 : Int8 to_i8, to_i8! : Int8 to_i8!, to_json(json : JSON::Builder) to_json, to_s(io : IO) : Nil
to_s : String to_s, to_u128 : UInt128 to_u128, to_u128! : UInt128 to_u128!, to_u16 : UInt16 to_u16, to_u16! : UInt16 to_u16!, to_u32 : UInt32 to_u32, to_u32! : UInt32 to_u32!, to_u64 : UInt64 to_u64, to_u64! : UInt64 to_u64!, to_u8 : UInt8 to_u8, to_u8! : UInt8 to_u8!, to_yaml(yaml : YAML::Nodes::Builder) to_yaml, value : Int value

### Constructor methods inherited from struct `Enum`

from_value(value : Int) : self from_value, new(ctx : YAML::ParseContext, node : YAML::Nodes::Node)
new(value : self)
new(pull : JSON::PullParser) new, parse(string : String) : self parse

### Class methods inherited from struct `Enum`

each(& : self -> ) each, from_value?(value : Int) : self | Nil from_value?, names : Array(String) names, parse?(string : String) : self | Nil parse?, valid?(value : self) : Bool valid?, values : Array(self) values

### Macros inherited from struct `Enum`

[](*values) [], flags(*values) flags

### Instance methods inherited from module `Comparable(Enum)`

<(other : T) : Bool <, <=(other : T) <=, <=>(other : T) <=>, ==(other : T) ==, >(other : T) : Bool >, >=(other : T) >=, clamp(min, max)
clamp(range : Range) clamp

### Instance methods inherited from struct `Value`

==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup

### Instance methods inherited from class `Object`

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

### Class methods inherited from class `Object`

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

### Macros inherited from class `Object`

class_getter(*names, &block) class_getter, class_getter!(*names) class_getter!, class_getter?(*names, &block) class_getter?, class_property(*names, &block) class_property, class_property!(*names) class_property!, class_property?(*names, &block) class_property?, class_setter(*names) class_setter, def_clone def_clone, def_equals(*fields) def_equals, def_equals_and_hash(*fields) def_equals_and_hash, def_hash(*fields) def_hash, delegate(*methods, to object) delegate, forward_missing_to(delegate) forward_missing_to, getter(*names, &block) getter, getter!(*names) getter!, getter?(*names, &block) getter?, property(*names, &block) property, property!(*names) property!, property?(*names, &block) property?, setter(*names) setter

##
Instance Method Detail

def acquire? #
def acquire_release? #
def relaxed? #
def release? #
def sequentially_consistent? #