What's a good class for writing a Log File Class?

[usmarine]

Ideally you should put this functionality in a service add write to it via shared memory. The event log is sort of one example of this but has limitations.

[petru66]

Martin,

Thanks a lot for your answer!

It seems that I found the right person to ask questions

It so happens, that I have to write a trace-log class. I have to trace function calls - too fast for TimeStamp to be of any use, but that's another problem, and I solved it somehow.

Anyway, the problem is this: There are hundreds of thousands of messages to be logged, during the whole execution of the application. I keep the file open, because otherwise the overload for opening/closing would be exceedingly high. I am very upset because it is not properly closed. There is no method explicitly called when the application exists, therefore the only place where I could put the close is in Dispose; which is never called!!!

Perhaps you have an idea...

Thanks,
Petru

[MartinL]

Hm... Sure, place it to Dispose() method...

However Dispose() is called from the destructor. We are dealing with garbage collector in .net so destructor calls are not deterministic...

Garbage collector examines so-called application roots maintained by the CLR. When the object is not reacheble from any application roots it is free to deletion. The process of deletion is called Garbage Collecting. (it is not just about deleting unreachable objects. It is also about moving objects among the generations - internal structure of gargbage collector) However you don't exactely know when that occures. It may be immediatelly after you close tha application or even half a hour after quitting your app...

Fortunatelly you can force this garbage collecting. There is a class GC in System namespace. You can use System.GC.Collect() method to perform the garbage collecting immediatelly. It will imediatelly call destructor and Dispose() method of that object.

You need to handle request to quit the application. And you can call GC.Collect() there...

martin

[Harshit]

well may be i m too late but just wanted to share somthing which you guys might be knowing already..but for those who dont..

we actually dont need to invoke the garbage collector manually just for the heck of calling dispose() method of any particular class.. a good solution will be to use using statement like this..

using (Resource res = new Resource()) {
res.DoWork();
}

the above code is as good as the following..

Resource res = new Resource(...);
try {
res.DoWork();
}
finally {
if (res != null) ((IDisposable)res).Dispose();
}

so it calls the dispose() method automatically when u are done with ur object.

-Harshit

[MartinL]

Yes, it is true... However it works only when you exactelly know where you object does the job... It is impossible to use if the object should be alive during the whole programe execution and should be destroyed before you program finishes...

martin

[tillu]

Isn't there some overhead for opening and closing file every time application writes something?

I have a very hihg performance required console application that does a lot of logging. Is it going to slow it down if log file is opened aand losed frequently?

Thanks.

[TheCPUWizard]

Posting my two cents on the "keep open"/"open on demand" issue. I have faced this many times. There are issues with both.

For a top performance class, I will typically use a timer. A write to the file resets the timer. If the timer expires, i close the file.

My timer is typically on the order of 1 second.

Now the file is closed "most of the time", bu remains open between successive calls within a short duration.