package main

// Go makes it possible to recover from a panic, by using the
// recover built-in function. A recover can stop a panic from
// aborting the program and let it continue with execution instead.

// An example of where this can be useful: a server wouldn't want to
// crash if one of the client connections exhibits a critical error.
// Instead, the server would want to close that connection and continue
// serving other clients. In fact, this is what Go's net/http does
// by default for HTTP servers.

import "fmt"

// This function panics.
func mayPanic() {
	panic("a problem")
}

func main() {
	// recover must be called within a deferred function. When the
	// enclosing function panics, the defer will activate and a
	// recover call within it will catch the panic.
	defer func() {
		if r := recover(); r != nil {
			fmt.Println("Recovered. Error:\n", r)
		}
	}()

	mayPanic()

	// This code will not run, because mayPanic() panics.
	// The execution of main stops at the point of the panic and
	// resumes in the deferred closure.
	fmt.Println("After mayPanic()")
}