Re: [Pika-dev] C argument type for indices?

[Tom Lord]

    > From: Andreas Rottmann <address@hidden>

    > Tom Lord <address@hidden> writes:

    > > (`int' is fine for the number of limbs and limb indexes -- just not
    > > for elt offsets into limbs.  `int' is similarly fine for vtable-object
    > > slot indexes.)

    > So I guess you want t_uint for elt offsets into limbs?

No, ssize_t.

The rule is:

  * signed integers for indexes  -- mostly so that functions 
    can return either a valid index or -1.

  * ssize_t for indexes of things that are of indefinate size --
    such as limb elements

  * int for indexes for things that are guaranteed small in number 
    -- such as vtable object slots and vtable limbs

  * t_scm_fixnum for hash values -- which aren't indexes but which we
    want to give to and get back from Scheme as fixnums, not bignums


-t