From: ts <decoux@...>
Date: 2003-04-03T23:29:08+09:00
Subject: Re: Strange behavior in C-declared global variable?

>>>>> "J" == =?iso-8859-1?Q?Jos=E9?= Augusto <iso-8859-1> writes:

J>     static VALUE newvar(int argc, VALUE *argv, VALUE self) {
J>       VALUE temp;

J>       temp = rb_ary_new();
J>       rb_ary_push(temp, rb_float_new(3.3));
J>       rb_define_variable("$tempor", &temp);
J>       rb_global_variable(&temp);
J>       return Qnil;
J>     }

 Don't do this rb_define_variable() and rb_global_variable() must be used
 *only* with "global" variables, like for example in

   /* see the declaration of temp0 and temp1 outside the function */
   static VALUE temp0, temp1;

   void Init_tt()
   {
       temp0 = rb_ary_new();
       temp1 = rb_ary_new();
       /*
          this variable can be accessed from ruby and C
       */
       rb_define_variable("$tempor", &temp0);
       /*
          this variable can be accessed only from C
          this is to protect it against the GC
       */
       rb_global_variable(&temp1);
   }


 In your case you want rb_gv_set(), rb_gv_get() (see p. 197 of the pickaxe)

 Something like this (not tested)

    static VALUE newvar(int argc, VALUE *argv, VALUE self) {
      VALUE temp;

      temp = rb_ary_new();
      rb_ary_push(temp, rb_float_new(3.3));
      rb_gv_set("$tempor", temp);
      return Qnil;
    }



Guy Decoux