Atomic enforces usage of its only safe constructor,
in contrast to std::atomic.
"The default-initialized std::atomic<T> does not contain
a T object, and its only valid uses are destruction and
initialization by std::atomic_init, see LWG issue 2334."
-- https://en.cppreference.com/w/cpp/atomic/atomic/atomic
`m_IsNoOp` was introduced to avoid building up log messages that will later be
discarded, like debug messages if no debug logging is configured. However, it
looks like the template operator<< implemented in the header file was forgotten
when adding this feature, all other places writing into `m_Buffer` already have
an if guard like added by this commit.
by caching the total minimum log severity of all loggers in a
"global variable" and whether a message's severity is large enough for any of
the loggers in a per-message no-op flag.
When Icinga 2 is started as a service, the early log messages generated
until the FileLogger object is activated are lost and make it really
hard to debug issues that (only) occur when Icinga 2 reloads.
With this commit, these early log messages are written to the Windows
Event Log.
Changed `--output-file` to `--output`
Default output file now has a timestamp in the name, no more overwriting
Added Section headers and file markers
Taken time is now measured and output
And some format changes were made
refs #3446
