Boost C++ Libraries: Ticket #12887: I had a problem with boost.log when set the filter with & operator

component changed; owner set

anonymous — Wed, 08 Mar 2017 03:48:15 GMT

owner set to Andrey Semashev
component None → log

status changed; resolution set

Andrey Semashev — Wed, 08 Mar 2017 09:16:48 GMT

status new → closed
resolution → wontfix

The problem is that the operator is applied to an instance of boost::log::value_ref, which is basically an optional reference to the actual attribute value. operator& cannot be applied to it because the reference can be empty (e.g. if the log record does not contain the attribute), and in this case the operator cannot return any meaningful result.

Currently, your best solution is to write your own filter function that will first test if the attribute value is found and then apply operator&.

bool my_filter(boost::log::value_ref<uint64, tag::attr_appenders> const& appenders)
{
    uint64 mask = 0x01ul << _id;
    if (appenders)
        return (appenders.get() & mask) != 0;
    else
        return false; // the default
}
sink->set_filter(boost::phoenix::bind(&my_filter, attr_appenders.or_none()));

status changed; resolution deleted

anonymous — Wed, 08 Mar 2017 09:20:09 GMT

status closed → reopened
resolution wontfix

status changed; resolution set

Andrey Semashev — Wed, 08 Mar 2017 09:31:50 GMT

status reopened → closed
resolution → wontfix

I'm not planning to fix it, since the error is the consequence of the library design.

Please, don't reopen, unless you have a suggested way to fix the problem.