Hi,
When I use boost::optional I often see gcc warnings about using possibly
uninitialized values. I've seen such warnings in my projects outside Boost but
now I encountered them in Boost.Log. Building the current develop with gcc 4.8
I see this:
./boost/date_time/constrained_value.hpp: In member function
‘boost::shared_ptrboost::log::v2_mt_posix::sinks::sink
boost::log::v2_mt_posix::
{anonymous}::default_text_file_sink_factory<CharT>::create_sink(const
settings_section&) [with CharT = wchar_t; boost::log::v2_mt_posix::
{anonymous}::default_text_file_sink_factory<CharT>::settings_section =
boost::log::v2_mt_posix::basic_settings_section]’:
./boost/date_time/constrained_value.hpp:76:7: warning: ‘*((void*)& day +2)’
may be used uninitialized in this function [-Wmaybe-uninitialized]
value_ = value;
^
libs/log/src/init_from_settings.cpp:172:32: note: ‘*((void*)& day +2)’ was
declared here
optional< unsigned short > day;
^
libs/log/src/init_from_settings.cpp:249:87: warning: ‘*((void*)& weekday +4)’
may be used uninitialized in this function [-Wmaybe-uninitialized]
return sinks::file::rotation_at_time_point(weekday.get(), hour,
minute, second);
^
libs/log/src/init_from_settings.cpp:171:37: note: ‘*((void*)& weekday +4)’ was
declared here
optional< date_time::weekdays > weekday;
^
I attached the full log for convenience. The code in question is this
function:
https://github.com/boostorg/log/blob/develop/src/init_from_settings.cpp#L171
Note that at line 248 and below I check that the optional is filled before
using it, so there is no way I'll be accessing any uninitialized data (that
is, if boost::optional behaves correctly).
I suspect this may be a compiler bug. I tried to create a minimal example to
reproduce it but the warning doesn't show in a simple context. However, I'd
like it to be worked around somehow (unless it's an actual bug in
boost::optional).
Any suggestions? Am I missing a bug in my code?
