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37 lines
944 B
Go
37 lines
944 B
Go
1 year ago
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// A race condition occurs in this program because two goroutines are attempting
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// to access a variable in shared memory `counter` concurrently.
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// One would expect that the value of coutner at the end of the run would be
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// 10,000 * 2 = 20,000 and on some runs it will produce this value. On other runs
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// one gorountine will read the counter value just before the second goroutine
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// writes to the shared variable. When the first goroutine writes it's counter value + 1
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// it overwrites the counter value with an older value + 1. This results in some runs
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// producing a counter result 1000s of values lower than expected.
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package main
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import (
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"fmt"
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"sync"
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)
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var counter int
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func main() {
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var wg sync.WaitGroup
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wg.Add(2)
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goroutine_count := 2
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for i := 0; i < goroutine_count; i++ {
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go func() {
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for i := 0; i < 10000; i++ {
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counter = counter + 1
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}
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wg.Done()
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}()
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}
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wg.Wait()
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fmt.Println("Counter:", counter)
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}
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