Documentation
¶
Overview ¶
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 ¶
- func And(ptr *uint32, val uint32)
- func And8(ptr *uint8, val uint8)
- func Cas(ptr *uint32, old, new uint32) bool
- func Cas64(ptr *uint64, old, new uint64) bool
- func CasRel(ptr *uint32, old, new uint32) bool
- func Casint32(ptr *int32, old, new int32) bool
- func Casint64(ptr *int64, old, new int64) bool
- func Casp1(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool
- func Casuintptr(ptr *uintptr, old, new uintptr) bool
- func Load(ptr *uint32) uint32
- func Load64(ptr *uint64) uint64
- func Load8(ptr *uint8) uint8
- func LoadAcq(ptr *uint32) uint32
- func LoadAcq64(ptr *uint64) uint64
- func LoadAcquintptr(ptr *uintptr) uintptr
- func Loadint32(ptr *int32) int32
- func Loadint64(ptr *int64) int64
- func Loadp(ptr unsafe.Pointer) unsafe.Pointer
- func Loaduint(ptr *uint) uint
- func Loaduintptr(ptr *uintptr) uintptr
- func Or(ptr *uint32, val uint32)
- func Or8(ptr *uint8, val uint8)
- func Store(ptr *uint32, val uint32)
- func Store64(ptr *uint64, val uint64)
- func Store8(ptr *uint8, val uint8)
- func StoreRel(ptr *uint32, val uint32)
- func StoreRel64(ptr *uint64, val uint64)
- func StoreReluintptr(ptr *uintptr, val uintptr)
- func Storeint32(ptr *int32, new int32)
- func Storeint64(ptr *int64, new int64)
- func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)
- func Storeuintptr(ptr *uintptr, new uintptr)
- func Xadd(ptr *uint32, delta int32) uint32
- func Xadd64(ptr *uint64, delta int64) uint64
- func Xaddint32(ptr *int32, delta int32) int32
- func Xaddint64(ptr *int64, delta int64) int64
- func Xadduintptr(ptr *uintptr, delta uintptr) uintptr
- func Xchg(ptr *uint32, new uint32) uint32
- func Xchg64(ptr *uint64, new uint64) uint64
- func Xchgint32(ptr *int32, new int32) int32
- func Xchgint64(ptr *int64, new int64) int64
- func Xchguintptr(ptr *uintptr, new uintptr) uintptr
- type Bool
- type Float64
- type Int32
- type Int64
- type Pointer
- type Uint32
- func (u *Uint32) Add(delta int32) uint32
- func (u *Uint32) And(value uint32)
- func (u *Uint32) CompareAndSwap(old, new uint32) bool
- func (u *Uint32) CompareAndSwapRelease(old, new uint32) bool
- func (u *Uint32) Load() uint32
- func (u *Uint32) LoadAcquire() uint32
- func (u *Uint32) Or(value uint32)
- func (u *Uint32) Store(value uint32)
- func (u *Uint32) StoreRelease(value uint32)
- func (u *Uint32) Swap(value uint32) uint32
- type Uint64
- type Uint8
- type Uintptr
- func (u *Uintptr) Add(delta uintptr) uintptr
- func (u *Uintptr) CompareAndSwap(old, new uintptr) bool
- func (u *Uintptr) Load() uintptr
- func (u *Uintptr) LoadAcquire() uintptr
- func (u *Uintptr) Store(value uintptr)
- func (u *Uintptr) StoreRelease(value uintptr)
- func (u *Uintptr) Swap(value uintptr) uintptr
- type UnsafePointer
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Casuintptr ¶
func LoadAcquintptr ¶ added in go1.16
func Loaduintptr ¶
func StoreRel64 ¶ added in go1.16
func StoreReluintptr ¶ added in go1.16
func Storeint32 ¶ added in go1.17
func Storeint64 ¶ added in go1.17
func StorepNoWB ¶ added in go1.7
StorepNoWB performs *ptr = val atomically and without a write barrier.
NO go:noescape annotation; see atomic_pointer.go.
func Storeuintptr ¶
func Xadduintptr ¶
func Xchguintptr ¶
Types ¶
type Bool ¶ added in go1.19
type Bool struct {
// contains filtered or unexported fields
}
Bool is an atomically accessed bool value.
A Bool must not be copied.
type Float64 ¶ added in go1.18
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.
type Int32 ¶ added in go1.18
type Int32 struct {
// contains filtered or unexported fields
}
Int32 is an atomically accessed int32 value.
An Int32 must not be copied.
func (*Int32) Add ¶ added in go1.18
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 ¶ added in go1.18
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.
type Int64 ¶ added in go1.18
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 ¶ added in go1.18
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 ¶ added in go1.18
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.
type Pointer ¶ added in go1.20
type Pointer[T any] struct { // contains filtered or unexported fields }
Pointer is an atomic pointer of type *T.
func (*Pointer[T]) CompareAndSwap ¶ added in go1.20
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 ¶ added in go1.20
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 ¶ added in go1.20
func (p *Pointer[T]) Load() *T
Load accesses and returns the value atomically.
func (*Pointer[T]) Store ¶ added in go1.20
func (p *Pointer[T]) Store(value *T)
Store updates the value atomically.
func (*Pointer[T]) StoreNoWB ¶ added in go1.20
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 ¶ added in go1.18
type Uint32 struct {
// contains filtered or unexported fields
}
Uint32 is an atomically accessed uint32 value.
A Uint32 must not be copied.
func (*Uint32) Add ¶ added in go1.18
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 ¶ added in go1.18
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 ¶ added in go1.18
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 ¶ added in go1.18
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) LoadAcquire ¶ added in go1.18
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 ¶ added in go1.18
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) StoreRelease ¶ added in go1.18
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.
type Uint64 ¶ added in go1.18
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 ¶ added in go1.18
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 ¶ added in go1.18
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) LoadAcquire ¶ added in go1.18
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) StoreRelease ¶ added in go1.18
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.
type Uint8 ¶ added in go1.18
type Uint8 struct {
// contains filtered or unexported fields
}
Uint8 is an atomically accessed uint8 value.
A Uint8 must not be copied.
func (*Uint8) And ¶ added in go1.18
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.
type Uintptr ¶ added in go1.18
type Uintptr struct {
// contains filtered or unexported fields
}
Uintptr is an atomically accessed uintptr value.
A Uintptr must not be copied.
func (*Uintptr) Add ¶ added in go1.18
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 ¶ added in go1.18
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) LoadAcquire ¶ added in go1.18
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) StoreRelease ¶ added in go1.18
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.
type UnsafePointer ¶ added in go1.18
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 ¶ added in go1.20
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 ¶ added in go1.18
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 ¶ added in go1.18
func (u *UnsafePointer) Load() unsafe.Pointer
Load accesses and returns the value atomically.
func (*UnsafePointer) Store ¶ added in go1.20
func (u *UnsafePointer) Store(value unsafe.Pointer)
Store updates the value atomically.
func (*UnsafePointer) StoreNoWB ¶ added in go1.18
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.
Source Files