exit work

src/028-interfaces/interfaces.go

@@ -7,3 +7,5 @@ import "fmt"
 type Shape interface {
     area() float64
 }
+
+// todo: that great blog post on interfaces

src/073-exit/.gitignore

@@ -0,0 +1 @@
+exit

src/073-exit/exit.go

@@ -1,16 +1,24 @@
-// Exit
-
-package main
+// ## Exit
 
 // Use `os.Exit` to immediatly exit with a given
 // status.
+
+package main
+
 import "os"
 
 func main() {
-    // This `println` will never be reached because the
-    // exit is immediate.
+    // `defer`s will _not_ be run when using `os.Exit`, so
+    // this `println` will never be called.
     defer println("!")
+
+    // Exit with status 3.
     os.Exit(3)
 }
 
+// Note that unlike e.g. C, Go does not use an integer
+// return value from `main` to indicate exit status. If
+// you'd like to exit with a non-zero status you should
+// use `os.Exit`.
+
 // todo: discuss building before getting here

src/073-exit/exit.sh

@@ -9,3 +9,5 @@ $ go build exit.go
 $ ./exit
 $ echo $?
 3
+
+# Note that the `!` from our program never got printed.