Re: [Log4cpp-devel] log4cpp problems

[Robert J. S. <r.s...@ch...>]

Op zondag 13 juli 2003 01:24, schreef David H. Lynch Jr.:
>     Atleast for me logging is a global function for the whole
> application. Therefore I need a global logger/category beyond the scope
> of of a single function.

Define this:

    Category&
    log()
    {
	static Category& l = Category::getInstance("my_category");
	return l;
    }

and then use it like this:

    log().debugStream() << "message";

I have such a log() function defined for every class, most of the time as a 
free function in the anonymous namespace and sometimes as a virtual 
protected/private member function.

>
>     I have been unable to declare a category object outside the confines
> of a function. 

You should declare a reference not an object, see above.

> Either there is not an appropriate constructor or the
> resulting program faults during initialization with a bad memory access.
> I can declare a global pointer to a category object, and assign it a
> value inside main, but some of the methods generate exceptions that do
> not appear to be documented when used in the pointer form cat->method()
> instead of cat.method();
>
> The problem here is more likely to lie with my early c++ skills rather
> than log4cpp but a clue would be appreciated.

It seems so, but until you post some code/error messages we won't know.


>     I have done numerous searches looking for documentation or sample
> applications that use log4cpp and there is a dearth of documentation
> available. I tend to find I learn more easily for examples, but the
> examples I have found are primarily the test samples that come with
> log4cpp, which are nice but either confine a category to the scope of a
> function or pass it as an argument neither of which are practical and
> violate the precept that the debugging is independent of the operation
> of the program being debugged.

I dont know what you mean by this precept (in what way independent?). Maybe 
that you want to strip all the logging code in release mode?

Logging != debugging. If only want to produce debug messages and want to strip 
this completely from your code in release mode then perhaps its beter to look 
for a macro based solution. This is not what log4cpp is about.