From: Andre Nathan <andre@...>
Date: 2013-03-11T21:03:51+09:00
Subject: Returning File::Stat objects from a C extension

Hello

I'm trying to find out how to return File::Stat objects from a C
extension. In 1.8 I can do it like this:

  #define WRAP_STAT(stp) Data_Wrap_Struct(rb_cStat, NULL, free, stp)

  static VALUE
  stat_new(struct stat *st)
  {
      struct stat *stp = ALLOC(struct stat);
      *stp = *st;
      return WRAP_STAT(stp);
  }

Starting in 1.9 it seems the correct way would be to do it like this:

  static size_t
  stat_memsize(const void *p)
  {
      return p ? sizeof(struct stat) : 0;
  }
  static const rb_data_type_t stat_data_type = {
      "stat",
      {NULL, RUBY_TYPED_DEFAULT_FREE, stat_memsize,},
  };
  #define WRAP_STAT(stp) \
      TypedData_Wrap_Struct(rb_cStat, &stat_data_type, stp)

However this leads to the following error:

#<File::Stat/usr/lib/ruby/1.9.1/pp.rb:405:in `dev': wrong argument type
stat (expected stat) (TypeError)

An analogous error also happens when I try to do the same for Dir
objects.

What is the correct way to do this?

Thanks in advance,
Andre