Checks the frozen object with `mrb_get_args()`

This now works with the `+` modifier that can be added after each specifier.

- `nil` is bypassed.
- The `s` and `z` specifiers are received in C as a `const char *`, so adding a `+` modifier will raise an exception.
- The `a` specifier is received in C as `const mrb_value *`, so adding a `+` modifier will raise an exception.
- The `|`, `*`, `&`, `?` and `:` specifiers with `+` modifier raises an exception.

If `!`/`+` exceeds one for each specifier, an exception will occur in the subsequent processing.
This is the same behavior as before.

1 files changed, 7 insertions, 0 deletions

diff --git a/include/mruby.h b/include/mruby.h
index 2a6bc7753..45736ba38 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -911,6 +911,13 @@ MRB_API struct RClass* mrb_define_module_under_id(mrb_state *mrb, struct RClass
  * | `:`  | keyword args   | {mrb_kwargs} const | Get keyword arguments. @see mrb_kwargs |
  *
  * @see mrb_get_args
+ *
+ * Immediately after format specifiers it can add format modifiers:
+ *
+ * | char | Notes                                                                                   |
+ * |:----:|-----------------------------------------------------------------------------------------|
+ * | `!`  | Switch to the alternate mode; The behaviour changes depending on the format specifier   |
+ * | `+`  | Request a not frozen object; However, except nil value                                  |
  */
 typedef const char *mrb_args_format;