From: Yukihiro Matsumoto <matz@...>
Date: 2008-01-08T09:34:48+09:00
Subject: Re: Using "sort!" in a C extension (1.9 problem)

Hi,

Sorry for being late to reply.  I have missed your mail.

In message "Re: Using "sort!" in a C extension (1.9 problem)"
    on Sun, 30 Dec 2007 02:49:47 +0900, Andre Nathan <andre@digirati.com.br> writes:

|In ruby 1.8, I could use Array#sort! in a C extension like this:
|
|static VALUE
|call_sort_bang(VALUE ary)
|{
|    return rb_funcall(ary, rb_intern("sort!"), 0);
|}
|
|static VALUE
|sort_i(VALUE ary)
|{
|    long v1 = FIX2LONG(RARRAY_PTR(ary)[0]);
|    long v2 = FIX2LONG(RARRAY_PTR(ary)[1]);
|    return LONG2FIX(v1 - v2);
|}
|
|static VALUE
|foo(void)
|{
|    VALUE ary = rb_ary_new();
|    rb_ary_push(ary, INT2FIX(1));
|    rb_ary_push(ary, INT2FIX(0));
|    rb_ary_push(ary, INT2FIX(2));
|    rb_iterate(call_sort_bang, ary, sort_i, 0);
|    rb_funcall(rb_mKernel, rb_intern("p"), 1, ary);
|    return a;
|}
|
|This would print "[0, 1, 2]" as expected. However, it doesn't work in
|ruby1.9 compiled from svn (checked out today). The problem seems to be
|that only one of the array elements is being passed to sort_i(), instead
|of a pair of elements as it's done in 1.8.
|
|What is the correct way to do this in 1.9?

In general, if you want to get multiple values from yield, you have to
use arguments added in 1.9:

static VALUE
sort_i(VALUE a1, VALUE a2, int argc, VALUE *argv)
{
    long v1 = FIX2LONG(RARRAY_PTR(argv[0]));
    long v2 = FIX2LONG(RARRAY_PTR(argv[1]));
    return LONG2FIX(v1 - v2);
}

You may need to check argc if they are variable.

							matz.