On Wed, Nov 07, 2001 at 12:39:32AM -0600, Rob Browning wrote:
> [EMAIL PROTECTED] writes:
> > So, if we replace malloc, we then need a table of pointers and their
> > size. Worth it?
>
> If we're going to be using it for anything substantial, I tend to
> think this would be *extremely* unwise. Writing a good allocator is
> *hard*.
>
> If the performance is critical, then I suspect we should use the
> system realloc if/when we can determine (via configure.in) that it's
> reliable, and otherwise, we should be using more explicit means.
> Using gnu libc's realloc certainly would have worked better in my
> case.
>
> Anyway from a quick glance, it looks like we're only using realloc for
> strings, which you can easily determine the length of, and for
> lt_caller_data which could be easily augmented to include a size
> field.
>
> So as one approach, we could just have str_realloc() and
> realloc_caller_data(), and then these could use the system realloc
> internally on platforms where that's considered beneficial.
According to ltdl.h,
/* By default, the realloc function pointer is set to our internal
realloc implementation which iself uses lt_dlmalloc and lt_dlfree.
libltdl relies on a featureful realloc, but if you are sure yours
has the right semantics then you can assign it directly. Generally,
it is safe to assign just a malloc() and a free() function. */
And, in ltdl.c:
/* These are the pointers that can be changed by the caller: */
LT_GLOBAL_DATA lt_ptr (*lt_dlmalloc) LT_PARAMS((size_t size))
= (lt_ptr (*) LT_PARAMS((size_t))) malloc;
LT_GLOBAL_DATA lt_ptr (*lt_dlrealloc) LT_PARAMS((lt_ptr ptr, size_t size))
= (lt_ptr (*) LT_PARAMS((lt_ptr, size_t))) rpl_realloc;
LT_GLOBAL_DATA void (*lt_dlfree) LT_PARAMS((lt_ptr ptr))
= (void (*) LT_PARAMS((lt_ptr))) free;
Because ltdl.h already states that libltdl relies on a featureful
realloc, let's just set lt_dlrealloc = realloc and test for a
featureful realloc in ltdl.m4. Let's recommend that if anyone changes
at least one of lt_dlmalloc, lt_dlrealloc, or lt_dlfree, then they
should also change them all. Let the client worry about malloc/free
and ltdl be somewhat stupid to the choices of the client.
--
albert chin ([EMAIL PROTECTED])
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