A panic halts normal execution flow and exits the current function. Any deferred calls will then be executed before control is passed to the next higher function on the stack. Each stack's function will exit and run deferred calls until the panic is handled using a deferred recover()
, or until the panic reaches main()
and terminates the program. If this occurs, the argument provided to panic and a stack trace will be printed to stderr
.
package main
import "fmt"
func foo() {
defer fmt.Println("Exiting foo")
panic("bar")
}
func main() {
defer fmt.Println("Exiting main")
foo()
}
Output:
Exiting foo
Exiting main
panic: bar
goroutine 1 [running]:
panic(0x128360, 0x1040a130)
/usr/local/go/src/runtime/panic.go:481 +0x700
main.foo()
/tmp/sandbox550159908/main.go:7 +0x160
main.main()
/tmp/sandbox550159908/main.go:12 +0x120
It is important to note that panic
will accept any type as its parameter.