Documentation
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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".
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 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 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)
- Bugs
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func AddUint32 ¶
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)).
func AddUint64 ¶
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)).
func AddUintptr ¶
AddUintptr atomically adds delta to *addr and returns the new value.
func CompareAndSwapInt32 ¶
CompareAndSwapInt32 executes the compare-and-swap operation for an int32 value.
func CompareAndSwapInt64 ¶
CompareAndSwapInt64 executes the compare-and-swap operation for an int64 value.
func CompareAndSwapPointer ¶
CompareAndSwapPointer executes the compare-and-swap operation for a unsafe.Pointer value.
func CompareAndSwapUint32 ¶
CompareAndSwapUint32 executes the compare-and-swap operation for a uint32 value.
func CompareAndSwapUint64 ¶
CompareAndSwapUint64 executes the compare-and-swap operation for a uint64 value.
func CompareAndSwapUintptr ¶
CompareAndSwapUintptr executes the compare-and-swap operation for a uintptr value.
func LoadPointer ¶
LoadPointer atomically loads *addr.
func LoadUintptr ¶
LoadUintptr atomically loads *addr.
func StoreInt32 ¶
StoreInt32 atomically stores val into *addr.
func StoreInt64 ¶
StoreInt64 atomically stores val into *addr.
func StorePointer ¶
StorePointer atomically stores val into *addr.
func StoreUint32 ¶
StoreUint32 atomically stores val into *addr.
func StoreUint64 ¶
StoreUint64 atomically stores val into *addr.
func StoreUintptr ¶
StoreUintptr atomically stores val into *addr.
func SwapPointer ¶
SwapPointer atomically stores new into *addr and returns the previous *addr value.
func SwapUint32 ¶
SwapUint32 atomically stores new into *addr and returns the previous *addr value.
func SwapUint64 ¶
SwapUint64 atomically stores new into *addr and returns the previous *addr value.
func SwapUintptr ¶
SwapUintptr atomically stores new into *addr and returns the previous *addr value.
Types ¶
This section is empty.
Notes ¶
Bugs ¶
On x86-32, the 64-bit functions use instructions unavailable before the Pentium MMX.
On non-Linux ARM, the 64-bit functions use instructions unavailable before the ARMv6k core.
On both ARM and x86-32, it is the caller's responsibility to arrange for 64-bit alignment of 64-bit words accessed atomically. The first word in a global variable or in an allocated struct or slice can be relied upon to be 64-bit aligned.
Source Files