From: "José Augusto" <jasa@...>
Date: 2003-04-05T00:00:23+09:00
Subject: Re: Strange behavior in C-declared global variable?

Hi

Thanks very much for your reply. You are right and declaring temp as static
solves the problem, as well as using rb_iv_set. The code
you suggested below works perfectly!

I examined the interrelation of rb_gv_set and rb_define_variable
in the  Ruby code (file variable.c) and posted my conclusions in other post
(replying to Kent Dahls' answer), so I dont repeat them here.

Thanks

J. Augusto

ts wrote:

> >>>>> "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