From: nobu.nokada@...
Date: 2003-07-02T22:43:48+09:00
Subject: Re: rb_gc() and scan stack

Hi,

At Wed, 2 Jul 2003 22:18:15 +0900,
Simon Strandgaard wrote:
> I tried drawing on some paper, what is happening..
> My initial drawing were wrong.. Now I understand.
> No problemo:

Incorrect.

G == rb_gc_stack_start  (set by Init_stack).

--[ 0 ]-----------------
bottom [.....................] top
        |

--[ 1 ]-----------------
entering ruby_init()
bottom [.......G.............] top
               |

--[ 2 ]-----------------
leaving ruby_init()
bottom [.RRRRRRG.............] top
         |

--[ 3 ]-----------------
entering Init_dummy()
bottom [..RRRRRG.............] top
          |

--[ 4 ]-----------------
leaving Init_dummy()
bottom [.RRRRRRG.............] top
         |

--[ 5 ]-----------------
entering test()
bottom [......RG.............] top
              |

--[ 6 ]-----------------
instance = Dummy.new
The instance is not within the mark-area, therefore it dies!
bottom [....i.RG.............] top
              |

> If we redo from step6 with Init_stack(begin).. with a
> lower begin address, then things will work.

--[ 6a ]-----------------
Init_stack(current_stack_ptr)
bottom [...G.................] top
           |

--[ 7a ]-----------------
instance = Dummy.new
This time the instance is within the area, and will thus survive
bottom [...GRiR..............] top
              |

-- 
Nobu Nakada