Package atomic

import "sync/atomic"
Overview
Index
Examples

Overview ▾

Package atomic provides low-level atomic memory primitives useful for implementing synchronization algorithms.

These functions require great care to be used correctly. Except for special, low-level applications, synchronization is better done with channels or the facilities of the sync package. Share memory by communicating; don't communicate by sharing memory.

The swap operation, implemented by the SwapT functions, is the atomic equivalent of:

old = *addr
*addr = new
return old

The compare-and-swap operation, implemented by the CompareAndSwapT functions, is the atomic equivalent of:

if *addr == old {
	*addr = new
	return true
}
return false

The add operation, implemented by the AddT functions, is the atomic equivalent of:

*addr += delta
return *addr

The load and store operations, implemented by the LoadT and StoreT functions, are the atomic equivalents of "return *addr" and "*addr = val".

In the terminology of the Go memory model, if the effect of an atomic operation A is observed by atomic operation B, then A “synchronizes before” B. Additionally, all the atomic operations executed in a program behave as though executed in some sequentially consistent order. This definition provides the same semantics as C++'s sequentially consistent atomics and Java's volatile variables.

Index ▾

func AddInt32(addr *int32, delta int32) (new int32)
func AddInt64(addr *int64, delta int64) (new int64)
func AddUint32(addr *uint32, delta uint32) (new uint32)
func AddUint64(addr *uint64, delta uint64) (new uint64)
func AddUintptr(addr *uintptr, delta uintptr) (new uintptr)
func AndInt32(addr *int32, mask int32) (old int32)
func AndInt64(addr *int64, mask int64) (old int64)
func AndUint32(addr *uint32, mask uint32) (old uint32)
func AndUint64(addr *uint64, mask uint64) (old uint64)
func AndUintptr(addr *uintptr, mask uintptr) (old uintptr)
func CompareAndSwapInt32(addr *int32, old, new int32) (swapped bool)
func CompareAndSwapInt64(addr *int64, old, new int64) (swapped bool)
func CompareAndSwapPointer(addr *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool)
func CompareAndSwapUint32(addr *uint32, old, new uint32) (swapped bool)
func CompareAndSwapUint64(addr *uint64, old, new uint64) (swapped bool)
func CompareAndSwapUintptr(addr *uintptr, old, new uintptr) (swapped bool)
func LoadInt32(addr *int32) (val int32)
func LoadInt64(addr *int64) (val int64)
func LoadPointer(addr *unsafe.Pointer) (val unsafe.Pointer)
func LoadUint32(addr *uint32) (val uint32)
func LoadUint64(addr *uint64) (val uint64)
func LoadUintptr(addr *uintptr) (val uintptr)
func OrInt32(addr *int32, mask int32) (old int32)
func OrInt64(addr *int64, mask int64) (old int64)
func OrUint32(addr *uint32, mask uint32) (old uint32)
func OrUint64(addr *uint64, mask uint64) (old uint64)
func OrUintptr(addr *uintptr, mask uintptr) (old uintptr)
func StoreInt32(addr *int32, val int32)
func StoreInt64(addr *int64, val int64)
func StorePointer(addr *unsafe.Pointer, val unsafe.Pointer)
func StoreUint32(addr *uint32, val uint32)
func StoreUint64(addr *uint64, val uint64)
func StoreUintptr(addr *uintptr, val uintptr)
func SwapInt32(addr *int32, new int32) (old int32)
func SwapInt64(addr *int64, new int64) (old int64)
func SwapPointer(addr *unsafe.Pointer, new unsafe.Pointer) (old unsafe.Pointer)
func SwapUint32(addr *uint32, new uint32) (old uint32)
func SwapUint64(addr *uint64, new uint64) (old uint64)
func SwapUintptr(addr *uintptr, new uintptr) (old uintptr)
type Bool
    func (x *Bool) CompareAndSwap(old, new bool) (swapped bool)
    func (x *Bool) Load() bool
    func (x *Bool) Store(val bool)
    func (x *Bool) Swap(new bool) (old bool)
type Int32
    func (x *Int32) Add(delta int32) (new int32)
    func (x *Int32) And(mask int32) (old int32)
    func (x *Int32) CompareAndSwap(old, new int32) (swapped bool)
    func (x *Int32) Load() int32
    func (x *Int32) Or(mask int32) (old int32)
    func (x *Int32) Store(val int32)
    func (x *Int32) Swap(new int32) (old int32)
type Int64
    func (x *Int64) Add(delta int64) (new int64)
    func (x *Int64) And(mask int64) (old int64)
    func (x *Int64) CompareAndSwap(old, new int64) (swapped bool)
    func (x *Int64) Load() int64
    func (x *Int64) Or(mask int64) (old int64)
    func (x *Int64) Store(val int64)
    func (x *Int64) Swap(new int64) (old int64)
type Pointer
    func (x *Pointer[T]) CompareAndSwap(old, new *T) (swapped bool)
    func (x *Pointer[T]) Load() *T
    func (x *Pointer[T]) Store(val *T)
    func (x *Pointer[T]) Swap(new *T) (old *T)
type Uint32
    func (x *Uint32) Add(delta uint32) (new uint32)
    func (x *Uint32) And(mask uint32) (old uint32)
    func (x *Uint32) CompareAndSwap(old, new uint32) (swapped bool)
    func (x *Uint32) Load() uint32
    func (x *Uint32) Or(mask uint32) (old uint32)
    func (x *Uint32) Store(val uint32)
    func (x *Uint32) Swap(new uint32) (old uint32)
type Uint64
    func (x *Uint64) Add(delta uint64) (new uint64)
    func (x *Uint64) And(mask uint64) (old uint64)
    func (x *Uint64) CompareAndSwap(old, new uint64) (swapped bool)
    func (x *Uint64) Load() uint64
    func (x *Uint64) Or(mask uint64) (old uint64)
    func (x *Uint64) Store(val uint64)
    func (x *Uint64) Swap(new uint64) (old uint64)
type Uintptr
    func (x *Uintptr) Add(delta uintptr) (new uintptr)
    func (x *Uintptr) And(mask uintptr) (old uintptr)
    func (x *Uintptr) CompareAndSwap(old, new uintptr) (swapped bool)
    func (x *Uintptr) Load() uintptr
    func (x *Uintptr) Or(mask uintptr) (old uintptr)
    func (x *Uintptr) Store(val uintptr)
    func (x *Uintptr) Swap(new uintptr) (old uintptr)
type Value
    func (v *Value) CompareAndSwap(old, new any) (swapped bool)
    func (v *Value) Load() (val any)
    func (v *Value) Store(val any)
    func (v *Value) Swap(new any) (old any)
Bugs

Examples

Value (Config)
Value (ReadMostly)

Package files

doc.go type.go value.go

func AddInt32

func AddInt32(addr *int32, delta int32) (new int32)

AddInt32 atomically adds delta to *addr and returns the new value. Consider using the more ergonomic and less error-prone Int32.Add instead.

func AddInt64

func AddInt64(addr *int64, delta int64) (new int64)

AddInt64 atomically adds delta to *addr and returns the new value. Consider using the more ergonomic and less error-prone Int64.Add instead (particularly if you target 32-bit platforms; see the bugs section).

func AddUint32

func AddUint32(addr *uint32, delta uint32) (new uint32)

AddUint32 atomically adds delta to *addr and returns the new value. To subtract a signed positive constant value c from x, do AddUint32(&x, ^uint32(c-1)). In particular, to decrement x, do AddUint32(&x, ^uint32(0)). Consider using the more ergonomic and less error-prone Uint32.Add instead.

func AddUint64

func AddUint64(addr *uint64, delta uint64) (new uint64)

AddUint64 atomically adds delta to *addr and returns the new value. To subtract a signed positive constant value c from x, do AddUint64(&x, ^uint64(c-1)). In particular, to decrement x, do AddUint64(&x, ^uint64(0)). Consider using the more ergonomic and less error-prone Uint64.Add instead (particularly if you target 32-bit platforms; see the bugs section).

func AddUintptr

func AddUintptr(addr *uintptr, delta uintptr) (new uintptr)

AddUintptr atomically adds delta to *addr and returns the new value. Consider using the more ergonomic and less error-prone Uintptr.Add instead.

func AndInt32 1.23

func AndInt32(addr *int32, mask int32) (old int32)

AndInt32 atomically performs a bitwise AND operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Int32.And instead.

func AndInt64 1.23

func AndInt64(addr *int64, mask int64) (old int64)

AndInt64 atomically performs a bitwise AND operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Int64.And instead.

func AndUint32 1.23

func AndUint32(addr *uint32, mask uint32) (old uint32)

AndUint32 atomically performs a bitwise AND operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Uint32.And instead.

func AndUint64 1.23

func AndUint64(addr *uint64, mask uint64) (old uint64)

AndUint64 atomically performs a bitwise AND operation on *addr using the bitmask provided as mask and returns the old. Consider using the more ergonomic and less error-prone Uint64.And instead.

func AndUintptr 1.23

func AndUintptr(addr *uintptr, mask uintptr) (old uintptr)

AndUintptr atomically performs a bitwise AND operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Uintptr.And instead.

func CompareAndSwapInt32

func CompareAndSwapInt32(addr *int32, old, new int32) (swapped bool)

CompareAndSwapInt32 executes the compare-and-swap operation for an int32 value. Consider using the more ergonomic and less error-prone Int32.CompareAndSwap instead.

func CompareAndSwapInt64

func CompareAndSwapInt64(addr *int64, old, new int64) (swapped bool)

CompareAndSwapInt64 executes the compare-and-swap operation for an int64 value. Consider using the more ergonomic and less error-prone Int64.CompareAndSwap instead (particularly if you target 32-bit platforms; see the bugs section).

func CompareAndSwapPointer

func CompareAndSwapPointer(addr *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool)

CompareAndSwapPointer executes the compare-and-swap operation for a unsafe.Pointer value. Consider using the more ergonomic and less error-prone Pointer.CompareAndSwap instead.

func CompareAndSwapUint32

func CompareAndSwapUint32(addr *uint32, old, new uint32) (swapped bool)

CompareAndSwapUint32 executes the compare-and-swap operation for a uint32 value. Consider using the more ergonomic and less error-prone Uint32.CompareAndSwap instead.

func CompareAndSwapUint64

func CompareAndSwapUint64(addr *uint64, old, new uint64) (swapped bool)

CompareAndSwapUint64 executes the compare-and-swap operation for a uint64 value. Consider using the more ergonomic and less error-prone Uint64.CompareAndSwap instead (particularly if you target 32-bit platforms; see the bugs section).

func CompareAndSwapUintptr

func CompareAndSwapUintptr(addr *uintptr, old, new uintptr) (swapped bool)

CompareAndSwapUintptr executes the compare-and-swap operation for a uintptr value. Consider using the more ergonomic and less error-prone Uintptr.CompareAndSwap instead.

func LoadInt32

func LoadInt32(addr *int32) (val int32)

LoadInt32 atomically loads *addr. Consider using the more ergonomic and less error-prone Int32.Load instead.

func LoadInt64

func LoadInt64(addr *int64) (val int64)

LoadInt64 atomically loads *addr. Consider using the more ergonomic and less error-prone Int64.Load instead (particularly if you target 32-bit platforms; see the bugs section).

func LoadPointer

func LoadPointer(addr *unsafe.Pointer) (val unsafe.Pointer)

LoadPointer atomically loads *addr. Consider using the more ergonomic and less error-prone Pointer.Load instead.

func LoadUint32

func LoadUint32(addr *uint32) (val uint32)

LoadUint32 atomically loads *addr. Consider using the more ergonomic and less error-prone Uint32.Load instead.

func LoadUint64

func LoadUint64(addr *uint64) (val uint64)

LoadUint64 atomically loads *addr. Consider using the more ergonomic and less error-prone Uint64.Load instead (particularly if you target 32-bit platforms; see the bugs section).

func LoadUintptr

func LoadUintptr(addr *uintptr) (val uintptr)

LoadUintptr atomically loads *addr. Consider using the more ergonomic and less error-prone Uintptr.Load instead.

func OrInt32 1.23

func OrInt32(addr *int32, mask int32) (old int32)

OrInt32 atomically performs a bitwise OR operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Int32.Or instead.

func OrInt64 1.23

func OrInt64(addr *int64, mask int64) (old int64)

OrInt64 atomically performs a bitwise OR operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Int64.Or instead.

func OrUint32 1.23

func OrUint32(addr *uint32, mask uint32) (old uint32)

OrUint32 atomically performs a bitwise OR operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Uint32.Or instead.

func OrUint64 1.23

func OrUint64(addr *uint64, mask uint64) (old uint64)

OrUint64 atomically performs a bitwise OR operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Uint64.Or instead.

func OrUintptr 1.23

func OrUintptr(addr *uintptr, mask uintptr) (old uintptr)

OrUintptr atomically performs a bitwise OR operation on *addr using the bitmask provided as mask and returns the old value. Consider using the more ergonomic and less error-prone Uintptr.Or instead.

func StoreInt32

func StoreInt32(addr *int32, val int32)

StoreInt32 atomically stores val into *addr. Consider using the more ergonomic and less error-prone Int32.Store instead.

func StoreInt64

func StoreInt64(addr *int64, val int64)

StoreInt64 atomically stores val into *addr. Consider using the more ergonomic and less error-prone Int64.Store instead (particularly if you target 32-bit platforms; see the bugs section).

func StorePointer

func StorePointer(addr *unsafe.Pointer, val unsafe.Pointer)

StorePointer atomically stores val into *addr. Consider using the more ergonomic and less error-prone Pointer.Store instead.

func StoreUint32

func StoreUint32(addr *uint32, val uint32)

StoreUint32 atomically stores val into *addr. Consider using the more ergonomic and less error-prone Uint32.Store instead.

func StoreUint64

func StoreUint64(addr *uint64, val uint64)

StoreUint64 atomically stores val into *addr. Consider using the more ergonomic and less error-prone Uint64.Store instead (particularly if you target 32-bit platforms; see the bugs section).

func StoreUintptr

func StoreUintptr(addr *uintptr, val uintptr)

StoreUintptr atomically stores val into *addr. Consider using the more ergonomic and less error-prone Uintptr.Store instead.

func SwapInt32 1.2

func SwapInt32(addr *int32, new int32) (old int32)

SwapInt32 atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Int32.Swap instead.

func SwapInt64 1.2

func SwapInt64(addr *int64, new int64) (old int64)

SwapInt64 atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Int64.Swap instead (particularly if you target 32-bit platforms; see the bugs section).

func SwapPointer 1.2

func SwapPointer(addr *unsafe.Pointer, new unsafe.Pointer) (old unsafe.Pointer)

SwapPointer atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Pointer.Swap instead.

func SwapUint32 1.2

func SwapUint32(addr *uint32, new uint32) (old uint32)

SwapUint32 atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Uint32.Swap instead.

func SwapUint64 1.2

func SwapUint64(addr *uint64, new uint64) (old uint64)

SwapUint64 atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Uint64.Swap instead (particularly if you target 32-bit platforms; see the bugs section).

func SwapUintptr 1.2

func SwapUintptr(addr *uintptr, new uintptr) (old uintptr)

SwapUintptr atomically stores new into *addr and returns the previous *addr value. Consider using the more ergonomic and less error-prone Uintptr.Swap instead.

type Bool 1.19

A Bool is an atomic boolean value. The zero value is false.

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

func (*Bool) CompareAndSwap 1.19

func (x *Bool) CompareAndSwap(old, new bool) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for the boolean value x.

func (*Bool) Load 1.19

func (x *Bool) Load() bool

Load atomically loads and returns the value stored in x.

func (*Bool) Store 1.19

func (x *Bool) Store(val bool)

Store atomically stores val into x.

func (*Bool) Swap 1.19

func (x *Bool) Swap(new bool) (old bool)

Swap atomically stores new into x and returns the previous value.

type Int32 1.19

An Int32 is an atomic int32. The zero value is zero.

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

func (*Int32) Add 1.19

func (x *Int32) Add(delta int32) (new int32)

Add atomically adds delta to x and returns the new value.

func (*Int32) And 1.23

func (x *Int32) And(mask int32) (old int32)

And atomically performs a bitwise AND operation on x using the bitmask provided as mask and returns the old value.

func (*Int32) CompareAndSwap 1.19

func (x *Int32) CompareAndSwap(old, new int32) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for x.

func (*Int32) Load 1.19

func (x *Int32) Load() int32

Load atomically loads and returns the value stored in x.

func (*Int32) Or 1.23

func (x *Int32) Or(mask int32) (old int32)

Or atomically performs a bitwise OR operation on x using the bitmask provided as mask and returns the old value.

func (*Int32) Store 1.19

func (x *Int32) Store(val int32)

Store atomically stores val into x.

func (*Int32) Swap 1.19

func (x *Int32) Swap(new int32) (old int32)

Swap atomically stores new into x and returns the previous value.

type Int64 1.19

An Int64 is an atomic int64. The zero value is zero.

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

func (*Int64) Add 1.19

func (x *Int64) Add(delta int64) (new int64)

Add atomically adds delta to x and returns the new value.

func (*Int64) And 1.23

func (x *Int64) And(mask int64) (old int64)

And atomically performs a bitwise AND operation on x using the bitmask provided as mask and returns the old value.

func (*Int64) CompareAndSwap 1.19

func (x *Int64) CompareAndSwap(old, new int64) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for x.

func (*Int64) Load 1.19

func (x *Int64) Load() int64

Load atomically loads and returns the value stored in x.

func (*Int64) Or 1.23

func (x *Int64) Or(mask int64) (old int64)

Or atomically performs a bitwise OR operation on x using the bitmask provided as mask and returns the old value.

func (*Int64) Store 1.19

func (x *Int64) Store(val int64)

Store atomically stores val into x.

func (*Int64) Swap 1.19

func (x *Int64) Swap(new int64) (old int64)

Swap atomically stores new into x and returns the previous value.

type Pointer

A Pointer is an atomic pointer of type *T. The zero value is a nil *T.

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

func (*Pointer[T]) CompareAndSwap

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

CompareAndSwap executes the compare-and-swap operation for x.

func (*Pointer[T]) Load

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

Load atomically loads and returns the value stored in x.

func (*Pointer[T]) Store

func (x *Pointer[T]) Store(val *T)

Store atomically stores val into x.

func (*Pointer[T]) Swap

func (x *Pointer[T]) Swap(new *T) (old *T)

Swap atomically stores new into x and returns the previous value.

type Uint32 1.19

A Uint32 is an atomic uint32. The zero value is zero.

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

func (*Uint32) Add 1.19

func (x *Uint32) Add(delta uint32) (new uint32)

Add atomically adds delta to x and returns the new value.

func (*Uint32) And 1.23

func (x *Uint32) And(mask uint32) (old uint32)

And atomically performs a bitwise AND operation on x using the bitmask provided as mask and returns the old value.

func (*Uint32) CompareAndSwap 1.19

func (x *Uint32) CompareAndSwap(old, new uint32) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for x.

func (*Uint32) Load 1.19

func (x *Uint32) Load() uint32

Load atomically loads and returns the value stored in x.

func (*Uint32) Or 1.23

func (x *Uint32) Or(mask uint32) (old uint32)

Or atomically performs a bitwise OR operation on x using the bitmask provided as mask and returns the old value.

func (*Uint32) Store 1.19

func (x *Uint32) Store(val uint32)

Store atomically stores val into x.

func (*Uint32) Swap 1.19

func (x *Uint32) Swap(new uint32) (old uint32)

Swap atomically stores new into x and returns the previous value.

type Uint64 1.19

A Uint64 is an atomic uint64. The zero value is zero.

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

func (*Uint64) Add 1.19

func (x *Uint64) Add(delta uint64) (new uint64)

Add atomically adds delta to x and returns the new value.

func (*Uint64) And 1.23

func (x *Uint64) And(mask uint64) (old uint64)

And atomically performs a bitwise AND operation on x using the bitmask provided as mask and returns the old value.

func (*Uint64) CompareAndSwap 1.19

func (x *Uint64) CompareAndSwap(old, new uint64) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for x.

func (*Uint64) Load 1.19

func (x *Uint64) Load() uint64

Load atomically loads and returns the value stored in x.

func (*Uint64) Or 1.23

func (x *Uint64) Or(mask uint64) (old uint64)

Or atomically performs a bitwise OR operation on x using the bitmask provided as mask and returns the old value.

func (*Uint64) Store 1.19

func (x *Uint64) Store(val uint64)

Store atomically stores val into x.

func (*Uint64) Swap 1.19

func (x *Uint64) Swap(new uint64) (old uint64)

Swap atomically stores new into x and returns the previous value.

type Uintptr 1.19

A Uintptr is an atomic uintptr. The zero value is zero.

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

func (*Uintptr) Add 1.19

func (x *Uintptr) Add(delta uintptr) (new uintptr)

Add atomically adds delta to x and returns the new value.

func (*Uintptr) And 1.23

func (x *Uintptr) And(mask uintptr) (old uintptr)

And atomically performs a bitwise AND operation on x using the bitmask provided as mask and returns the old value.

func (*Uintptr) CompareAndSwap 1.19

func (x *Uintptr) CompareAndSwap(old, new uintptr) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for x.

func (*Uintptr) Load 1.19

func (x *Uintptr) Load() uintptr

Load atomically loads and returns the value stored in x.

func (*Uintptr) Or 1.23

func (x *Uintptr) Or(mask uintptr) (old uintptr)

Or atomically performs a bitwise OR operation on x using the bitmask provided as mask and returns the updated value after the OR operation.

func (*Uintptr) Store 1.19

func (x *Uintptr) Store(val uintptr)

Store atomically stores val into x.

func (*Uintptr) Swap 1.19

func (x *Uintptr) Swap(new uintptr) (old uintptr)

Swap atomically stores new into x and returns the previous value.

type Value 1.4

A Value provides an atomic load and store of a consistently typed value. The zero value for a Value returns nil from Value.Load. Once Value.Store has been called, a Value must not be copied.

A Value must not be copied after first use.

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

Example (Config)

The following example shows how to use Value for periodic program config updates and propagation of the changes to worker goroutines.

Example (ReadMostly)

The following example shows how to maintain a scalable frequently read, but infrequently updated data structure using copy-on-write idiom.

func (*Value) CompareAndSwap 1.17

func (v *Value) CompareAndSwap(old, new any) (swapped bool)

CompareAndSwap executes the compare-and-swap operation for the Value.

All calls to CompareAndSwap for a given Value must use values of the same concrete type. CompareAndSwap of an inconsistent type panics, as does CompareAndSwap(old, nil).

func (*Value) Load 1.4

func (v *Value) Load() (val any)

Load returns the value set by the most recent Store. It returns nil if there has been no call to Store for this Value.

func (*Value) Store 1.4

func (v *Value) Store(val any)

Store sets the value of the Value v to val. All calls to Store for a given Value must use values of the same concrete type. Store of an inconsistent type panics, as does Store(nil).

func (*Value) Swap 1.17

func (v *Value) Swap(new any) (old any)

Swap stores new into Value and returns the previous value. It returns nil if the Value is empty.

All calls to Swap for a given Value must use values of the same concrete type. Swap of an inconsistent type panics, as does Swap(nil).

Bugs