Hi Andy, Sorry for not explaining the role of flush_log_cache() in the docs. The flush_log_cache() should be called after you've *initialized* all the logs (in other words, after you've added all appenders and/or modifiers). In your code, it should be: // note: no need for the below call // set_log_caching(true); logger l_lgArray("lgArray"); logger l_lgCout("lgCout"); add_appender("lgCout", write_to_cout); add_appender("lgArray", ts_appender( appender_array() .add(write_to_file("btArrayFile1.txt")) .add(write_to_file("btArrayFile2.txt")) .add(write_to_file("btArrayFile3.txt")) .add(write_to_file("btArrayFile4.txt")))); flush_log_cache(); ThreadTest(l_lgArray, 1, 20000); The purpose of flush_log_cache() is to flush everything you've written to logs, before they were ***fully initialized***. This is especially useful in case you do logging when static variables are initialized -- without this mechanism, logging would happen too soon, and would end up writing nowhere. Example: BOOST_DEFINE_LOG(app,"app"); BOOST_LOG(app) << "where does this get written?"; // [1] add_appender("app", write_to_cout); add_appender("app", write_to_debug); // here, it knows where to log [1] flush_log_cache(); As for making all pending writes complete -- this is a defect of ts_appender() class -- which I want to correct. Best, John
I'm not sure I understand correctly, but it appears that flush_log_cache in the logging library doesn't actually force everything in the pipeline to be written by the logging thread to be written. Empirically, it seems that I had to add a sleep to the end of my program to cause everything to be written. Code-review-wise, and here I'm pretty sure I don't completely understand, it appears that flush_log_cache pushes things further down the pipeline but doesn't actually synchronize (wait for) the writing thread to complete. It seems like there maybe should be some kind of routine that "blocks" until all pending writes are complete, maybe just a wrapper around the ability to request the writing thread to finish, and then wait for it to complete. Maybe this mechanism is already present? I suppose that brings up other complications, such as what if some other thread logs something after we've asked it to stop.
In the code I was testing, I had a ts_appender, to which I added a appender_array, to which I added 4 write_to_files. For ~ 10 seconds I wrote to the log. Then I call flush_log_cache. If I don't then sleep a few seconds, the files are not all identical.
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