New subject: [pacman-dev] [PATCH] alpm: Fix possible alignment issues w/ events

31 Dec 2015

      There are some warnings recently introduced when compiling with Clang (with
--enable-warningflags) for x86_64. The warnings are related to casting of
specific alpm_event-types to alpm_event_t where the required alignment
differs between the types. On x86, it shouldn't be a problem, but maybe
there are other architectures pacman should work on where this is a real
issue?
Either way, I think it would be good if pacman built cleanly with Clang. Any
suggestions on how to fix this?

For reference, the warnings are:

hook.c:732:3: warning: cast from 'alpm_event_hook_t *' (aka 'struct
_alpm_event_hook_t *') to 'alpm_event_t *' (aka 'union _alpm_event_t *')
increases required alignment from 4 to 8 [-Wcast-align]
                EVENT(handle, &event);
                ^~~~~~~~~~~~~~~~~~~~~
./handle.h:37:16: note: expanded from macro 'EVENT'
                (h)->eventcb((alpm_event_t *) (e)); \
                             ^~~~~~~~~~~~~~~~~~~~
hook.c:761:3: warning: cast from 'alpm_event_hook_t *' (aka 'struct
_alpm_event_hook_t *') to 'alpm_event_t *' (aka 'union _alpm_event_t *')
increases required alignment from 4 to 8 [-Wcast-align]
                EVENT(handle, &event);
                ^~~~~~~~~~~~~~~~~~~~~
./handle.h:37:16: note: expanded from macro 'EVENT'
                (h)->eventcb((alpm_event_t *) (e)); \
                             ^~~~~~~~~~~~~~~~~~~~
2 warnings generated.
trans.c:202:2: warning: cast from 'alpm_event_any_t *' (aka 'struct
_alpm_event_any_t *') to 'alpm_event_t *' (aka 'union _alpm_event_t *')
increases required alignment from 4 to 8 [-Wcast-align]
        EVENT(handle, &event);
        ^~~~~~~~~~~~~~~~~~~~~
./handle.h:37:16: note: expanded from macro 'EVENT'
                (h)->eventcb((alpm_event_t *) (e)); \
                             ^~~~~~~~~~~~~~~~~~~~
trans.c:226:3: warning: cast from 'alpm_event_any_t *' (aka 'struct
_alpm_event_any_t *') to 'alpm_event_t *' (aka 'union _alpm_event_t *')
increases required alignment from 4 to 8 [-Wcast-align]
                EVENT(handle, &event);
                ^~~~~~~~~~~~~~~~~~~~~
./handle.h:37:16: note: expanded from macro 'EVENT'
                (h)->eventcb((alpm_event_t *) (e)); \
                             ^~~~~~~~~~~~~~~~~~~~

[pacman-dev] Clang warnings

Rikard Falkeborn

Olivier Brunel

Allan McRae

Olivier Brunel

Rikard Falkeborn

Olivier Brunel

Allan McRae

Olivier Brunel

Rikard Falkeborn

Olivier Brunel

Andrew Gregory

Olivier Brunel

Allan McRae

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