On 22/03/2004, at 6:37 PM, John Torjo wrote:
Geoff Leyland wrote:
Hi,
Why not do something like
my_log("this_module_logging_flag_notes") << "Doing something in this_module"; my_log("that_module_logging_flag_errors") << "Something went wrong in that_module";
where a log object is either (depending on a compile time setting) a proxy for a stream or a not_logger than has
this is not such a hard thing to do ;) I've implemented some log classes like this in the (far) past ;) But what you would actually want is an enumerator or something, so that you can write things like:
log<error>() << "some error"; log<activity>() << "some activity";
That's not a bad idea! I tend to work with the idea that either I want no logging at all, with no code generated, or that logging is built in and I'm prepared to take quite a hit for its overhead. I like using strings for keys because I'm too disorganised to get all the enums I need in one place in a large project. However I think in a lot of cases, string keys would be to heavy for the run-time decision "log or not", which needs to be quick, even if you're generating the (large) stream code. Perhaps a log with a policy for setting how to decide whether to be on or off? I have vague mis-memories of X "atoms" which might have been something like void large_function(void) { unsigned activity_log(get_log_index("my_activity")); ... log(activity_index) << "blah"; ... } Which means you get the indexes organised at run-time, but only suffer the map search once per file/module/dll or whatever. cheers, Geoff