I need to add logging functionality for an existing code, based on a result of an operation. I was thinking of creating a class that when constructed receives a condition function and a function for execution, and based on the result of the condition, the code will be executed.

Example:

class auto_logger{

public:
auto_logger(const std::function<bool()>& cond,
            const std::function<void()>& func): _cond(cond), _func(func) {}

virtual ~auto_logger()
{
    try {
        if (_cond()) {
            _func();
        }
    } catch (...) {
        
    }
}


private:
    std::function<bool()> _cond;
    std::function<void()>  _func;
};

I will use this class like this:

int existing_func()
{
    int res = FAILURE;

    // this is the only additional code
    auto_logger logger([&](){
        return res == SUCCESS;
    },
    [](){
        print_to_log();
    });

    do_some_stuff_that_may_throw();

    res = perform_operation();

    return res;

} 

I would be happy to get some comments on this code. are there any problem I am not seeing in this solution, are there any better solutions?

I need to add logging functionality for an existing code, based on a result of an operation. I was thinking of creating a class that, when constructed, receives a condition function and a function for execution. Based on the result of the condition, the code will be executed.

Example:

class auto_logger{

public:
auto_logger(const std::function<bool()>& cond,
            const std::function<void()>& func): _cond(cond), _func(func) {}

virtual ~auto_logger()
{
    try {
        if (_cond()) {
            _func();
        }
    } catch (...) {
        
    }
}


private:
    std::function<bool()> _cond;
    std::function<void()>  _func;
};

I will use this class like this:

int existing_func()
{
    int res = FAILURE;

    // this is the only additional code
    auto_logger logger([&](){
        return res == SUCCESS;
    },
    [](){
        print_to_log();
    });

    do_some_stuff_that_may_throw();

    res = perform_operation();

    return res;

}

I would be happy to get some comments on this code. Are there any problem I am not seeing in this solution? Are there any better solutions?