package atomic

import "runtime/internal/atomic"

Package atomic provides atomic operations, independent of sync/atomic, to the runtime.

On most platforms, the compiler is aware of the functions defined in this package, and they're replaced with platform-specific intrinsics. On other platforms, generic implementations are made available.

Unless otherwise noted, operations defined in this package are sequentially consistent across threads with respect to the values they manipulate. More specifically, operations that happen in a specific order on one thread, will always be observed to happen in exactly that order by another thread.

Index

Functions

func And

func And(ptr *uint32, val uint32)

func And32

func And32(ptr *uint32, val uint32) uint32

func And64

func And64(ptr *uint64, val uint64) uint64

func And8

func And8(ptr *uint8, val uint8)

func Anduintptr

func Anduintptr(ptr *uintptr, val uintptr) uintptr

func Cas

func Cas(ptr *uint32, old, new uint32) bool

func Cas64

func Cas64(ptr *uint64, old, new uint64) bool

func CasRel

func CasRel(ptr *uint32, old, new uint32) bool

func Casint32

func Casint32(ptr *int32, old, new int32) bool

func Casint64

func Casint64(ptr *int64, old, new int64) bool

func Casp1

func Casp1(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool

NO go:noescape annotation; see atomic_pointer.go.

func Casuintptr

func Casuintptr(ptr *uintptr, old, new uintptr) bool

func Load

func Load(ptr *uint32) uint32

func Load64

func Load64(ptr *uint64) uint64

func Load8

func Load8(ptr *uint8) uint8

func LoadAcq

func LoadAcq(ptr *uint32) uint32

func LoadAcq64

func LoadAcq64(ptr *uint64) uint64

func LoadAcquintptr

func LoadAcquintptr(ptr *uintptr) uintptr

func Loadint32

func Loadint32(ptr *int32) int32

func Loadint64

func Loadint64(ptr *int64) int64

func Loadp

func Loadp(ptr unsafe.Pointer) unsafe.Pointer

func Loaduint

func Loaduint(ptr *uint) uint

func Loaduintptr

func Loaduintptr(ptr *uintptr) uintptr

func Or

func Or(ptr *uint32, val uint32)

func Or32

func Or32(ptr *uint32, val uint32) uint32

func Or64

func Or64(ptr *uint64, val uint64) uint64

func Or8

func Or8(ptr *uint8, val uint8)

func Oruintptr

func Oruintptr(ptr *uintptr, val uintptr) uintptr

func Store

func Store(ptr *uint32, val uint32)

func Store64

func Store64(ptr *uint64, val uint64)

func Store8

func Store8(ptr *uint8, val uint8)

func StoreRel

func StoreRel(ptr *uint32, val uint32)

func StoreRel64

func StoreRel64(ptr *uint64, val uint64)

func StoreReluintptr

func StoreReluintptr(ptr *uintptr, val uintptr)

func Storeint32

func Storeint32(ptr *int32, new int32)

func Storeint64

func Storeint64(ptr *int64, new int64)

func StorepNoWB

func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)

StorepNoWB performs *ptr = val atomically and without a write barrier.

NO go:noescape annotation; see atomic_pointer.go.

func Storeuintptr

func Storeuintptr(ptr *uintptr, new uintptr)

func Xadd

func Xadd(ptr *uint32, delta int32) uint32

func Xadd64

func Xadd64(ptr *uint64, delta int64) uint64

func Xaddint32

func Xaddint32(ptr *int32, delta int32) int32

func Xaddint64

func Xaddint64(ptr *int64, delta int64) int64

func Xadduintptr

func Xadduintptr(ptr *uintptr, delta uintptr) uintptr

func Xchg

func Xchg(ptr *uint32, new uint32) uint32

func Xchg64

func Xchg64(ptr *uint64, new uint64) uint64

func Xchgint32

func Xchgint32(ptr *int32, new int32) int32

func Xchgint64

func Xchgint64(ptr *int64, new int64) int64

func Xchguintptr

func Xchguintptr(ptr *uintptr, new uintptr) uintptr

Types

type Bool

type Bool struct {
	// contains filtered or unexported fields
}

Bool is an atomically accessed bool value.

A Bool must not be copied.

func (*Bool) Load

func (b *Bool) Load() bool

Load accesses and returns the value atomically.

func (*Bool) Store

func (b *Bool) Store(value bool)

Store updates the value atomically.

type Float64

type Float64 struct {
	// contains filtered or unexported fields
}

Float64 is an atomically accessed float64 value.

8-byte aligned on all platforms, unlike a regular float64.

A Float64 must not be copied.

func (*Float64) Load

func (f *Float64) Load() float64

Load accesses and returns the value atomically.

func (*Float64) Store

func (f *Float64) Store(value float64)

Store updates the value atomically.

type Int32

type Int32 struct {
	// contains filtered or unexported fields
}

Int32 is an atomically accessed int32 value.

An Int32 must not be copied.

func (*Int32) Add

func (i *Int32) Add(delta int32) int32

Add adds delta to i atomically, returning the new updated value.

This operation wraps around in the usual two's-complement way.

func (*Int32) CompareAndSwap

func (i *Int32) CompareAndSwap(old, new int32) bool

CompareAndSwap atomically compares i's value with old, and if they're equal, swaps i's value with new. It reports whether the swap ran.

func (*Int32) Load

func (i *Int32) Load() int32

Load accesses and returns the value atomically.

func (*Int32) Store

func (i *Int32) Store(value int32)

Store updates the value atomically.

func (*Int32) Swap

func (i *Int32) Swap(new int32) int32

Swap replaces i's value with new, returning i's value before the replacement.

type Int64

type Int64 struct {
	// contains filtered or unexported fields
}

Int64 is an atomically accessed int64 value.

8-byte aligned on all platforms, unlike a regular int64.

An Int64 must not be copied.

func (*Int64) Add

func (i *Int64) Add(delta int64) int64

Add adds delta to i atomically, returning the new updated value.

This operation wraps around in the usual two's-complement way.

func (*Int64) CompareAndSwap

func (i *Int64) CompareAndSwap(old, new int64) bool

CompareAndSwap atomically compares i's value with old, and if they're equal, swaps i's value with new. It reports whether the swap ran.

func (*Int64) Load

func (i *Int64) Load() int64

Load accesses and returns the value atomically.

func (*Int64) Store

func (i *Int64) Store(value int64)

Store updates the value atomically.

func (*Int64) Swap

func (i *Int64) Swap(new int64) int64

Swap replaces i's value with new, returning i's value before the replacement.

type Pointer

type Pointer[T any] struct {
	// contains filtered or unexported fields
}

Pointer is an atomic pointer of type *T.

func (*Pointer[T]) CompareAndSwap

func (p *Pointer[T]) CompareAndSwap(old, new *T) bool

CompareAndSwap atomically (with respect to other methods) compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

func (*Pointer[T]) CompareAndSwapNoWB

func (p *Pointer[T]) CompareAndSwapNoWB(old, new *T) bool

CompareAndSwapNoWB atomically (with respect to other methods) compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

WARNING: As the name implies this operation does *not* perform a write barrier on value, and so this operation may hide pointers from the GC. Use with care and sparingly. It is safe to use with values not found in the Go heap. Prefer CompareAndSwap instead.

func (*Pointer[T]) Load

func (p *Pointer[T]) Load() *T

Load accesses and returns the value atomically.

func (*Pointer[T]) Store

func (p *Pointer[T]) Store(value *T)

Store updates the value atomically.

func (*Pointer[T]) StoreNoWB

func (p *Pointer[T]) StoreNoWB(value *T)

StoreNoWB updates the value atomically.

WARNING: As the name implies this operation does *not* perform a write barrier on value, and so this operation may hide pointers from the GC. Use with care and sparingly. It is safe to use with values not found in the Go heap. Prefer Store instead.

type Uint32

type Uint32 struct {
	// contains filtered or unexported fields
}

Uint32 is an atomically accessed uint32 value.

A Uint32 must not be copied.

func (*Uint32) Add

func (u *Uint32) Add(delta int32) uint32

Add adds delta to u atomically, returning the new updated value.

This operation wraps around in the usual two's-complement way.

func (*Uint32) And

func (u *Uint32) And(value uint32)

And takes value and performs a bit-wise "and" operation with the value of u, storing the result into u.

The full process is performed atomically.

func (*Uint32) CompareAndSwap

func (u *Uint32) CompareAndSwap(old, new uint32) bool

CompareAndSwap atomically compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

func (*Uint32) CompareAndSwapRelease

func (u *Uint32) CompareAndSwapRelease(old, new uint32) bool

CompareAndSwapRelease is a partially unsynchronized version of Cas that relaxes ordering constraints. Other threads may observe operations that occur after this operation to precede it, but no operation that precedes it on this thread can be observed to occur after it. It reports whether the swap ran.

WARNING: Use sparingly and with great care.

func (*Uint32) Load

func (u *Uint32) Load() uint32

Load accesses and returns the value atomically.

func (*Uint32) LoadAcquire

func (u *Uint32) LoadAcquire() uint32

LoadAcquire is a partially unsynchronized version of Load that relaxes ordering constraints. Other threads may observe operations that precede this operation to occur after it, but no operation that occurs after it on this thread can be observed to occur before it.

WARNING: Use sparingly and with great care.

func (*Uint32) Or

func (u *Uint32) Or(value uint32)

Or takes value and performs a bit-wise "or" operation with the value of u, storing the result into u.

The full process is performed atomically.

func (*Uint32) Store

func (u *Uint32) Store(value uint32)

Store updates the value atomically.

func (*Uint32) StoreRelease

func (u *Uint32) StoreRelease(value uint32)

StoreRelease is a partially unsynchronized version of Store that relaxes ordering constraints. Other threads may observe operations that occur after this operation to precede it, but no operation that precedes it on this thread can be observed to occur after it.

WARNING: Use sparingly and with great care.

func (*Uint32) Swap

func (u *Uint32) Swap(value uint32) uint32

Swap replaces u's value with new, returning u's value before the replacement.

type Uint64

type Uint64 struct {
	// contains filtered or unexported fields
}

Uint64 is an atomically accessed uint64 value.

8-byte aligned on all platforms, unlike a regular uint64.

A Uint64 must not be copied.

func (*Uint64) Add

func (u *Uint64) Add(delta int64) uint64

Add adds delta to u atomically, returning the new updated value.

This operation wraps around in the usual two's-complement way.

func (*Uint64) CompareAndSwap

func (u *Uint64) CompareAndSwap(old, new uint64) bool

CompareAndSwap atomically compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

func (*Uint64) Load

func (u *Uint64) Load() uint64

Load accesses and returns the value atomically.

func (*Uint64) LoadAcquire

func (u *Uint64) LoadAcquire() uint64

LoadAcquire is a partially unsynchronized version of Load that relaxes ordering constraints. Other threads may observe operations that precede this operation to occur after it, but no operation that occurs after it on this thread can be observed to occur before it.

WARNING: Use sparingly and with great care.

func (*Uint64) Store

func (u *Uint64) Store(value uint64)

Store updates the value atomically.

func (*Uint64) StoreRelease

func (u *Uint64) StoreRelease(value uint64)

StoreRelease is a partially unsynchronized version of Store that relaxes ordering constraints. Other threads may observe operations that occur after this operation to precede it, but no operation that precedes it on this thread can be observed to occur after it.

WARNING: Use sparingly and with great care.

func (*Uint64) Swap

func (u *Uint64) Swap(value uint64) uint64

Swap replaces u's value with new, returning u's value before the replacement.

type Uint8

type Uint8 struct {
	// contains filtered or unexported fields
}

Uint8 is an atomically accessed uint8 value.

A Uint8 must not be copied.

func (*Uint8) And

func (u *Uint8) And(value uint8)

And takes value and performs a bit-wise "and" operation with the value of u, storing the result into u.

The full process is performed atomically.

func (*Uint8) Load

func (u *Uint8) Load() uint8

Load accesses and returns the value atomically.

func (*Uint8) Or

func (u *Uint8) Or(value uint8)

Or takes value and performs a bit-wise "or" operation with the value of u, storing the result into u.

The full process is performed atomically.

func (*Uint8) Store

func (u *Uint8) Store(value uint8)

Store updates the value atomically.

type Uintptr

type Uintptr struct {
	// contains filtered or unexported fields
}

Uintptr is an atomically accessed uintptr value.

A Uintptr must not be copied.

func (*Uintptr) Add

func (u *Uintptr) Add(delta uintptr) uintptr

Add adds delta to u atomically, returning the new updated value.

This operation wraps around in the usual two's-complement way.

func (*Uintptr) CompareAndSwap

func (u *Uintptr) CompareAndSwap(old, new uintptr) bool

CompareAndSwap atomically compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

func (*Uintptr) Load

func (u *Uintptr) Load() uintptr

Load accesses and returns the value atomically.

func (*Uintptr) LoadAcquire

func (u *Uintptr) LoadAcquire() uintptr

LoadAcquire is a partially unsynchronized version of Load that relaxes ordering constraints. Other threads may observe operations that precede this operation to occur after it, but no operation that occurs after it on this thread can be observed to occur before it.

WARNING: Use sparingly and with great care.

func (*Uintptr) Store

func (u *Uintptr) Store(value uintptr)

Store updates the value atomically.

func (*Uintptr) StoreRelease

func (u *Uintptr) StoreRelease(value uintptr)

StoreRelease is a partially unsynchronized version of Store that relaxes ordering constraints. Other threads may observe operations that occur after this operation to precede it, but no operation that precedes it on this thread can be observed to occur after it.

WARNING: Use sparingly and with great care.

func (*Uintptr) Swap

func (u *Uintptr) Swap(value uintptr) uintptr

Swap replaces u's value with new, returning u's value before the replacement.

type UnsafePointer

type UnsafePointer struct {
	// contains filtered or unexported fields
}

UnsafePointer is an atomically accessed unsafe.Pointer value.

Note that because of the atomicity guarantees, stores to values of this type never trigger a write barrier, and the relevant methods are suffixed with "NoWB" to indicate that explicitly. As a result, this type should be used carefully, and sparingly, mostly with values that do not live in the Go heap anyway.

An UnsafePointer must not be copied.

func (*UnsafePointer) CompareAndSwap

func (u *UnsafePointer) CompareAndSwap(old, new unsafe.Pointer) bool

CompareAndSwap atomically compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

func (*UnsafePointer) CompareAndSwapNoWB

func (u *UnsafePointer) CompareAndSwapNoWB(old, new unsafe.Pointer) bool

CompareAndSwapNoWB atomically (with respect to other methods) compares u's value with old, and if they're equal, swaps u's value with new. It reports whether the swap ran.

WARNING: As the name implies this operation does *not* perform a write barrier on value, and so this operation may hide pointers from the GC. Use with care and sparingly. It is safe to use with values not found in the Go heap. Prefer CompareAndSwap instead.

func (*UnsafePointer) Load

func (u *UnsafePointer) Load() unsafe.Pointer

Load accesses and returns the value atomically.

func (*UnsafePointer) Store

func (u *UnsafePointer) Store(value unsafe.Pointer)

Store updates the value atomically.

func (*UnsafePointer) StoreNoWB

func (u *UnsafePointer) StoreNoWB(value unsafe.Pointer)

StoreNoWB updates the value atomically.

WARNING: As the name implies this operation does *not* perform a write barrier on value, and so this operation may hide pointers from the GC. Use with care and sparingly. It is safe to use with values not found in the Go heap. Prefer Store instead.