[Olena-patches] [PATCH 2/4] Honor strict-aliasing rules in memset_.

* mln/data/memset_.hh (mln::data::impl::memset): Here. --- milena/ChangeLog | 6 ++++++ milena/mln/data/memset_.hh | 16 ++++++++++++---- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/milena/ChangeLog b/milena/ChangeLog index fc516e7..4caaa0a 100644 --- a/milena/ChangeLog +++ b/milena/ChangeLog @@ -1,5 +1,11 @@ 2009-10-06 Roland Levillain <roland(a)lrde.epita.fr> + Honor strict-aliasing rules in memset_. + + * mln/data/memset_.hh (mln::data::impl::memset): Here. + +2009-10-06 Roland Levillain <roland(a)lrde.epita.fr> + Warn about a bug in memcpy_ with g++ 4.2 on Debian for IA-32. * mln/data/memcpy_.hh (mln::data::impl::memcpy_): Here. diff --git a/milena/mln/data/memset_.hh b/milena/mln/data/memset_.hh index 4559e05..42b1412 100644 --- a/milena/mln/data/memset_.hh +++ b/milena/mln/data/memset_.hh @@ -1,4 +1,5 @@ -// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE) +// Copyright (C) 2007, 2008, 2009 EPITA Research and Development +// Laboratory (LRDE) // // This file is part of Olena. // @@ -101,9 +102,16 @@ namespace mln if (sizeof(mln_value(I)) == 1) { - std::memset((void*)(& pix.val()), - *(const int*)(&v), // violent cast - n); + /* Because of strict-aliasing rules, we cannot use + + *(const int*)(&v) + + as second argument for std::memset. Hence the use of + std::memcpy. See the `-fstrict-aliasing' entry in GCC's + documentation for more information. */ + char c; + std::memcpy(&c, &v, 1); + std::memset((void*)(& pix.val()), c, n); } else { -- 1.6.3.1