41 lines
1.2 KiB
Go
41 lines
1.2 KiB
Go
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// Package atomicx extends sync/atomic.
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//
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// Sync/atomic fails when using int64 atomic operations on 32 bit platforms
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// when the access is not aligned. As specified in the documentation, in
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// fact, "it is the caller's responsibility to arrange for 64-bit alignment
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// of 64-bit words accessed atomically". For more information on this
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// issue, see https://golang.org/pkg/sync/atomic/#pkg-note-BUG.
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//
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// As explained in CONTRIBUTING.md, probe-cli SHOULD use this package rather
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// than sync/atomic to avoid these alignment issues on 32 bit.
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//
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// It is of course possible to write atomic code using 64 bit variables on a
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// 32 bit platform, but that's difficult to do correctly. This package
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// provides an easier-to-use interface. We use allocated
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// structures protected by a mutex that encapsulate a int64 value.
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package atomicx
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import "sync"
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// Int64 is an int64 with atomic semantics.
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type Int64 struct {
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// mu provides mutual exclusion.
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mu sync.Mutex
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// v is the underlying value.
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v int64
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}
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// Add behaves like atomic.AddInt64.
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func (i64 *Int64) Add(delta int64) int64 {
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i64.mu.Lock()
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defer i64.mu.Unlock()
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i64.v += delta
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return i64.v
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}
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// Load behaves like atomic.LoadInt64.
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func (i64 *Int64) Load() (v int64) {
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return i64.Add(0)
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}
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