The file name rule for daily rotate log?

I posted a [thread on stackoverflow](https://stackoverflow.com/questions/46094193/boost-log-doesnt-write-log-to-the-file-which-has-max-file-counter-or-create-new) few months ago, no one answered it. It's not very urgent since it is only log file name so I just left it.

Recently I noticed that the [changelog of 1.66.0](http://www.boost.org/doc/libs/1_66_0/libs/log/doc/html/log/changelog.html) said it has been fixed.

For me I still have some issues about the file name. I can see some log file names after I upgrade boost to 1.66.0 just like it behaves in 1.65.1.

Here's the code:
```
logging::wsettings settings;
settings["Core"]["Filter"] = L"%Severity% >= debug";
settings["Core"]["DisableLogging"] = false;
settings["Sinks.File"]["Destination"] = L"TextFile";
settings["Sinks.File"]["FileName"] = L"App_%Y-%m-%d.%N.log";
settings["Sinks.File"]["Format"] = L"%TimeStamp% [%ThreadID%] %Severity(format=\"%-7s\")% - %Message%";
settings["Sinks.File"]["AutoFlush"] = true;
settings["Sinks.File"]["RotationTimePoint"] = L"00:00:00";
settings["Sinks.File"]["RotationSize"] = 10 * 1024 * 1024;
settings["Sinks.File"]["Target"] = filePath_;
settings["Sinks.File"]["ScanForFiles"] = L"All";
settings["Sinks.File"]["Append"] = true;
```

Here's some log file examples:
> App_2018-01-09.7.log
> App_2018-01-10.8.log
> App_2018-01-10.0.log
> App_2018-01-11.1.log
> App_2018-01-11.0.log
> (Sorted by creation time ASC)

My understanding is that **the counter** and **date-time part** are **unrelated**, the counter increases whenever a new file is being created. Is my understanding correct?

But this makes the file names confusing. For example:

1. Start app on 2018-01-11, then the file name is App_2018-01-11.0.log
2. A new filename will be created as App_2018-01-12.1.log tomorrow
3. If I restart app tomorrow, then a new filename created as App_2018-01-12.0.log

Is this the **current behavior**?
If so, my **suggestion** is to reset the file counter for a new day like this:

1. Start app on 2018-01-11, then the file name is App_2018-01-11.0.log
2. A new filename created as App_2018-01-12.0.log tomorrow
3. If I restart app tomorrow, then a new filename will be created as App_2018-01-12.0.log
4. If the file becomes too large, then the file counter will be increased when creating new file name.

Does this make sense?