From: viisi@... (Andreas Riedl)
Date: 2001-05-18T02:11:24+09:00
Subject: [ruby-talk:15333] how to use garbage collection relyably?

hi!

how is garbage collection intended to be used?

is

  VALUE x = rb_ary_new();
  VALUE y = rb_ary_new();

ensured to work correctly?

or must it be written as:

  VALUE x,y;

  x = rb_ary_new();
  rb_register_addr(&x);	
  y = rb_ary_new();
  rb_unregister_addr(&x);

to prevent the allocation of 'y' to accidentionally
recycle 'x''s space, before any other object is set up
to mark 'x'.

or should i 'GC.disable' globally and manually call
rb_gc() periodically from some save location. (where
it is ensured that there don't exist any temporary VALUE's)


btw:
i wonder how does it work in the ruby core?

e.g. in 'array.c':

----------- snip --------------
rb_ary_new2(len)
    long len;
{
    NEWOBJ(ary, struct RArray);
    OBJSETUP(ary, rb_cArray, T_ARRAY);
    .
    .
    .

    ary->ptr = ALLOC_N(VALUE, len);
}
----------- snap --------------

what prevents 'ALLOC_N(VALUE,len)' from just recycling 'ary',
if 'ruby_xmalloc' decides to call 'rb_gc'?

ciao, andi