Debugging heap corruption

[Vladimir Panteleev]

On Mon, 30 Jul 2007 13:16:32 +0300, Regan Heath <regan at netmail.co.nz> wrote:

> I haven't heard of "Phobos's GC SENTINEL option" what is it?  Where can
> I read about it in the D docs?

I described it in the original post. It is unfinished and thus undocumented. Quoted:

> I noticed that Phobos's GC has some debug code for "underrun/overrrun protection" [sic] in phobos\internal\gc\gcx.d, however I found that the code is unfinished. For some reason the corresponding code is put in "version (SENTINEL)" blocks, instead of "debug (SENTINEL)" ones - which would explain why it never worked (there is also a typo in code on line 567). Even with those obvious mistakes fixed, I have no idea how much work would be required to get the SENTINEL debug option working, since it's interfering with other language features such as array concatenation, and firing off false alarms.

>> I assume that what you said doesn't apply to D?
>
> I'm not sure what you mean?  Which part of what I said are you assuming doesn't apply to D?

If what you said applies to D, then you must have used your own allocation routines only in your own code (I.E. you don't hook D's memory allocation), since you didn't know if it's possible to substitute the standard "global allocator". In that case, your code will have the same effect as using libc's malloc() and Valgrind (except your code wouldn't be able to detect immediately when an overflow has happened). See the rest of this thread for details (particularly my reply to Matthias).

-- 
Best regards,
  Vladimir                          mailto:thecybershadow at gmail.com