The problem you want to solve here is that the logger is only initialized after options are parsed, but the parser might want to log an error. The reason that the logger needs input options is that there can be an input option that specifies a logfile sink.

My suggestion: Initialize the logger without a file sink before parsing the options, and if there is a file sink argument, add the sink to the logger after parsing.
This can either be achieved by slightly refactoring the logger class to offer a set_log_stream(), or just remove the logger and add a new one with a file sink.
This way, we can use the logger and, thus, our exit macro everywhere and have better consistency.

I agree with @FG-TUM . We could "just" move the init of the Logger from the else clause to some position before the option parsing. Keep in mind that PR #306 is not based on the latest master and a scope was introduced in the meantime.

I agree, that moving the logger in front would be the way to go. However, for the MPI there is still the problem that the logger currently requires MPI to be initialized inside the constructor as it calls MPI_Comm_rank ... So there will be a bit more refactoring necessary, i.e., removing the MPI dependence from inside the logger...

Note also, that I'd like to have reusable code for other projects, e.g., the option parser was originally a stand-alone thing and could be used in other projects that do not come with ls1 infrastructure (https://github.com/weisslj/cpp-optparse)

I agree, that moving the logger in front would be the way to go. However, for the MPI there is still the problem that the logger currently requires MPI to be initialized inside the constructor as it calls MPI_Comm_rank ... So there will be a bit more refactoring necessary, i.e., removing the MPI dependence from inside the logger...

Agreed that this dependency can be removed. So we just take the rank id as an argument for the constructor. Yet, I see no need to initialize the logger before MPI_Init(). If that one fails we can't don't log that anyway and just crash with the MPI error. But querying our rank id and initializing the logger with it can immediately be the next thing we do after init.

Note also, that I'd like to have reusable code for other projects, e.g., the option parser was originally a stand-alone thing and could be used in other projects that do not come with ls1 infrastructure (https://github.com/weisslj/cpp-optparse)

If it is copied into the ls1 project, it is fair game. Otherwise, it should be a third party dependency and loaded as such like ADIOS, ALL, AutoPas, ...

Closing in favour of the cleaner solution in #359.