Go by Example: Recover
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A |
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package main
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import (
"fmt"
)
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func main() {
recoverFromPanic(-1)
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We see it because we recovered from a panic. |
fmt.Printf("Finished without panicing.")
}
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recover is always defined in a defer. |
func recoverFromPanic(i int) {
defer func() {
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if r := recover(); r != nil {
fmt.Println("Recovered. Error:\n", r)
}
}()
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fmt.Printf("About to process i=%d\n", i)
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if i < 0 {
panic(fmt.Errorf("Accepting only"+
" non-negative numbers but received %d", i))
}
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We won’t see this because we paniced. |
fmt.Printf("Doing something with %d\n", i)
}
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Running this program will exit correctly, even though panic was called. |
$ go run recover.go
About to process i=-1
Recovered. Error:
Accepting only non-negative numbers but received -1
Finished without panicing.
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Note that, in Go it is idiomatic to use error-indicating return values wherever possible. |
Next example: Collection Functions.