Re: bounds checking in array.hpp

From: deansturtevant_at_[hidden]
Date: 2000-12-18 17:51:40

--- In boost_at_[hidden], Jesse Jones <jejones_at_a...> wrote:
> >
> >typedef bool (*assertion_failure_fcn)(void* arg, const char* file,
> >unsigned line, const char* message);
> 
> What's arg for?
> 
It's a standard technique when defining callbacks. It allows the 
client to specify data associated with the callback. Perhaps a 
superior approach is:

class assertion_failure_handler
{
 public:
    virtual bool handle_assertion_failure(
        const char* file, unsigned line, const char* message) = 0;
};

void set_assertion_failure_handler(assertion_failure_handler*);

Note that the callback's name is very descriptive. That's my taste, 
and comes in useful for classes that derive from multiple bases.