On Fri, Nov 1, 2019 at 1:45 AM Ivan Zhakov <i...@visualsvn.com> wrote:
> On Wed, 30 Oct 2019 at 13:18, Yann Ylavic <ylavic....@gmail.com> wrote: > > > > On Wed, Oct 30, 2019 at 4:37 AM William A Rowe Jr <wr...@rowe-clan.net> > wrote: > > > > > > On Wed, Oct 16, 2019 at 5:11 AM <i...@apache.org> wrote: > > >> > > >> Author: ivan > > >> Date: Wed Oct 16 10:10:59 2019 > > >> New Revision: 1868502 > > >> > > >> URL: http://svn.apache.org/viewvc?rev=1868502&view=rev > > >> Log: > > >> * atomic/win32/apr_atomic64.c > > >> (apr_atomic_read64): Use direct memory read when compiled for > x86_x64, since > > >> 64-bit reads are atomic in 64-bit Windows [1]. > > >> > > >> + /* > https://docs.microsoft.com/en-us/windows/win32/sync/interlocked-variable-access > > >> + * "Simple reads and writes to properly aligned 64-bit variables > are atomic > > >> + * on 64-bit Windows."*/ > > >> + return *mem; > > > > > > Where are we[1] ensuring *mem is aligned on an 8 byte boundary? > > > > Since mem is apr_uint64_t, unless the caller is playing nasty casts we > > should be good, I think. > I was envisioning more packed struct alignments... > +1. > > Also InterlockedCompareExchange64() as all other interlocked function > requires aligned data [1]. So APR already assumes that data is > properly aligned. > > [1] > https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange64 Agreed. It would be good to leave a breadcrumb in the doxygen that we require the pointers are using correct word alignment, and even the patch I hinted at wouldn't be improved given the ICEx docs.
