Boost log autoflush does not work for files - c++

Question

I'm using boost 1.63 for logging with the following line of code to use Boost config file for logging:
Logger::initFromConfig(logConfigName);
I decided so because I want it to be configurable and this way I could save myself from understanding Boost log setup API. Config file contents are:
[Core]
DisableLogging="false"
[Sinks.SYSLF]
Destination="TextFile"
Asynchronous="true"
AutoFlush="true"
Format="[%TimeStamp(format=\"%Y-%m-%d %H:%M:%S.%f\")%][%Severity%] %Message%"
Target="logs"
FileName="dsmip_%N.log"
RotationTimePoint="00:00:00"
ScanForFiles="Matching"
MaxSize="10000000"
Filter="%Severity% >= info"
[Sinks.Console]
Destination="Console"
AutoFlush="true"
Format="[%TimeStamp(format=\"%Y-%m-%d %H:%M:%S.%f\")%][%Severity%] %Message%"
Filter="%Severity% >= debug"
My problem is autoflush does not work for files. On stdout I get every event instantly, but the files are written first when I exit the application. This is quite embarassing for logging...
First I used 1.58, the situation was the same. What do I do wrong?
Thank you in advance.
Best regards: Balazs Bamer

Answer 1

Google was my friend, I have found the solution here. Boost really operates such that it creates the log file in the application directory, and only copies it to the destination when it is closed (log rotates or the program exists). So, in order to get all the log files appear in a specific directory, one has to include the directory name in the filename pattern as well as in the target.
[Sinks.SYSLF]
...
Target="logs"
FileName="logs/dsmip_%N.log"
Best regards: Balazs