uninitialized std::tm

[Johan Lundberg <lundberj@…>]

The struct std::tm seems uninitialized, or have possibly uninitialized members in a few places.

For example in ​https://svn.boost.org/trac/boost/changeset/85610

The most common patterns in boost seems to be to do

  std::tm x;
  std::memset(&x, 0, sizeof(x)); 

which seems good.

Some different/missing/suspicious initializations:

boost/log/detail/decomposed_time.hpp:    std::tm res = {};
boost/chrono/io/time_point_io.hpp (possibly several)

util/gregorian.cpp - the gregorian_calendar class members

boost/date_time/microsec_time_clock.hpp      
 (std::tm curr possibly not fully initialized)

[viboes]

Committed [85706]

[viboes]

(In [85816]) Chrono: initialize std::tm variables to all 0 to fix #9147.