Opened 5 years ago

Closed 5 years ago

#6922 closed Bugs (fixed)

gcc -Wcast-align warning in boost/intrusive

Reported by: stieber.c@… Owned by: igaztanaga
Milestone: To Be Determined Component: intrusive
Version: Boost 1.49.0 Severity: Cosmetic
Keywords: intrusive containers, member hook, alignment warning Cc:


When I tried to use boost::intrusive::set with a member hook, I got this warning (I use reasonably aggressive warning settings):

../../Boost/boost/intrusive/detail/parent_from_member.hpp:50:9: error: cast from 'char *' to 'CSBuilder::Project *'

increases required alignment from 1 to 8 [-Werror,-Wcast-align]

return (Parent*)((char*)member - offset_from_pointer_to_member(ptr_to_member));

I didn't dig into that code, but judging from the identifiers it seems to do the right thing, and it would seem that the warning is not caused by me doing something bad (unless you count using boost or enabling warnings as 'bad'). Thus, suppressing the warning is probably ok. Just insert an additional (void*) cast like this:

return (Parent*)(void*)((char*)member...

If other compilers "see through" that and still issue such warnings, somebody with more compiler-experience can probably come up with a better way.

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Change History (1)

comment:1 Changed 5 years ago by igaztanaga

  • Resolution set to fixed
  • Status changed from new to closed

Thanks for the report, it was corrected in trunk at revision 78588

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