From: Daniel Andersson <m10434_at@...>
Date: 2001-09-26T17:11:33+09:00
Subject: [ruby-talk:21713] Embedding woes

Hello,

I'm trying to embed ruby in a windows application. Ruby crashes when I
try to define a class (rb_define_class).

A detailed explaination:

First I download and build ruby:

----8x----8x----8x----8x----8x----8x----


D:\Download\>gzip -d ruby-1.6.5.tar.gz
D:\Download\>tar xf ruby-1.6.5.tar
D:\Download\>cd ruby-1.6.5
D:\Download\ruby-1.6.5>win32\configure.bat
type `nmake' to make ruby for mswin32.
D:\Download\ruby-1.6.5>nmake
<snip>
D:\Download\ruby-1.6.5>nmake test

Microsoft (R) Program Maintenance Utility   Version 6.00.8168.0
Copyright (C) Microsoft Corp 1988-1998. All rights reserved.

test succeeded

D:\Download\ruby-1.6.5>ls -l mswin32-ruby16.dll mswin32-ruby16.lib
-rw-rw-rw-   1 user     group      983098 Sep 25 22:31 mswin32-ruby16.dll
-rw-rw-rw-   1 user     group      684534 Sep 25 22:31 mswin32-ruby16.lib

D:\Download\ruby-1.6.5>

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Then the test program (doesn't do much but it shows the problem)

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#include "ruby.h"
#pragma comment(lib,"D:\\Download\\ruby-1.6.5\\mswin32-ruby16.lib")

int main(int argc, char **argv)
{
        VALUE classtest;

        ruby_init();
        ruby_script("embedded");
        rb_eval_string("puts \"foo\"");
        classtest = rb_define_class("TestClass", rb_cObject);

        return 0;
}

----8x----8x----8x----8x----8x----8x----

It compiles and links just fine. After putting the dll somewhere
where it can be found (ie the same dir as the .exe) I try to run
the program and the output is:

foo

and then it crashes. Running it through a debugger shows that it
crashes here:

class.c: 134

RBASIC(klass)->klass = rb_singleton_class_new(RBASIC(super)->klass);

        id      0x0000200d
        klass   0x00a3b4e8
        super   0x42ac25ff

in this function, super is whatever I supplied as the super-class in
my call to rb_define_class (rb_cObject).

Now I looked at line 130 in class.c:

if (!super) super = rb_cObject;

So it defaults to rb_cObject if I supply 0 as super-class. When I
try this (classtest = rb_define_class("TestClass", 0);) the app doesn't
crash.

Further debugging shows that the rb_cObject in my test app and the one
in class.c aren't the same:

in class.c:
        rb_cObject      0x00a4a998

in my test main.c:
        rb_cObject      0x42a025ff

What have I done wrong?

The program is compiled with Visual C++ 6.0

Any comments are welcome

Daniel Andersson