43 lines
1.1 KiB
Go
43 lines
1.1 KiB
Go
// Basic sends and receives on channels are blocking
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// use select with a default clause to implement non-blocking
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package main
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import "fmt"
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func main() {
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messages := make(chan string)
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signals := make(chan bool)
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// non-blocking receive
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// if a value is available on messages then select will take the <-messages case with that value
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// if not it will immediately take the default case
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select {
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case msg := <-messages:
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fmt.Println("received message", msg)
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default:
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fmt.Println("no message received")
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}
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// non-blocking send
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// msg cannot be sent to the messages channel, because the channel has no buffer and there is no receiver
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// Therefore the default case is selected.
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msg := "hi"
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select {
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case messages <- msg:
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fmt.Println("sent message", msg)
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default:
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fmt.Println("no message sent")
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}
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// use multiple cases above the default clause to implement a multi-way non-blocking select
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// here non-blocking receives on both messages and signals
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select {
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case msg := <-messages:
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fmt.Println("received message", msg)
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case sig := <-signals:
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fmt.Println("received signal", sig)
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default:
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fmt.Println("no activity")
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}
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}
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