diff --git a/src/crystal/main.cr b/src/crystal/main.cr
index a5c7ed00b369..641d1dd1402d 100644
--- a/src/crystal/main.cr
+++ b/src/crystal/main.cr
@@ -79,7 +79,7 @@ module Crystal
   #
   # ```
   # fun main(argc : Int32, argv : UInt8**) : Int32
-  #   LibFoo.init_foo_and_invoke_main(argc, argv, ->Crystal.main)
+  #   LibFoo.init_foo_and_invoke_main(argc, argv, ->Crystal.main(Int32, UInt8**))
   # end
   # ```
   #