[fpc-pascal] valgrind: "invalid read"

[Pierre Free Pascal]

> -----Message d'origine-----
> De : fpc-pascal-bounces at lists.freepascal.org [mailto:fpc-pascal-
> bounces at lists.freepascal.org] De la part de Jonas Maebe
> Envoyé : jeudi 4 juin 2015 19:51
> À : FPC-Pascal users discussions
> Objet : Re: [fpc-pascal] valgrind: "invalid read"
> 
> 
> David Emerson wrote on Thu, 04 Jun 2015:
> 
> > I have just started using valgrind, and I was surprised that I got a
> > lot of errors, particularly in places that look like clean code. So
> > I whittled things down and created a test program. Here is the error
> > I am seeing (I've removed the procid, ==11180==):
> >
> > Invalid read of size 16
> >    at 0x401727: SYSTEM_INDEXBYTE$formal$INT64$BYTE$$INT64 (in
> > /Docs/fpc/test/vg_stringlist_const_error)
> 
> It's a false positive. You can create valgrind suppression files to
> filter out such false positives. Someone once started a generic
> suppression file for FPC
> (http://svn.freepascal.org/svn/fpcbuild/trunk/install/unix/valgrind-
> fpc.supp
> ), but as you can see it's far from complete. You can even get
> Valgrind to generate the suppression itself when it prints out errors:
> http://valgrind.org/docs/manual/manual-core.html (search for
> --gen-suppressions=yes).

  Hi Jonas,

I am not sure I understand why it is a false positive:

The read size is 16, at offset 16, which make it read up to position 32,
while only 30 byte were allocated...
  What is wrong in my analysis above?

Pierre