On Thu, Aug 20, 2009 at 2:59 PM, Adam Badura<abadura@o2.pl> wrote:
Taking into account our previous discussions I expected that you will rather try to convince me that what I was going to do is bad rather then try to add non-const get_error_info. :)
The reputation I got, Jesus. :)
Alternatively, you can collect them all into a std::vector<boost::exception_ptr>. When you're done calling onNotifys, if the vector is not empty you just throw an exception, adding the vector to it.
If you are concerned about the (remote?) possibility of a std::bad_alloc propagating instead of your exceptions, you shouldn't be because that could happen anyway. To throw an exceptoin, the runtime needs memory to store the exception object. In some implementations that memory comes from the heap, so an attempt to throw any exception whatsoever could result in a std::bad_alloc instead (the runtime is required to have enough memory to throw a std::bad_alloc.)
Yes. I described that method as an alternative. And yes I am concerned with risk of std::bad_alloc. And yes I cannot avoid it fully anyway. But Boost exceptions objects are small so the risk is marginal. And if this happens anyway then I consider it an error so fatal that I will not recover from it anyway - just unwind the stack. Just because you cannot avoid accident does not meant that you will put yourself to an unnecessary risk, right?
Are you sure the reserve() will reduce the risk significantly? Note that boost::exception_ptr itself also allocates memory, not to mention the onNotify functions themselves, assuming they aren't trivial they could be allocating things as well.
Want another example? What about stack trace? I could have a sequence container in the exception and in each catch in which I will rethrow the exception I would add source code location data to have better diagnostic information. Obviously I cannot do this with fixed number of separate error_infos (without loss of data).
Yes that's a good one though the stack trace should be captured in one go before you throw. The trouble is this isn't possible in a platform-independent way; I'm hoping someone will come up with platform-specific implementation. I will add this support as soon as it's available, I do believe it is a very valuable diagnostic tool.
But I will not only defend myself but rather strike back now! :) (Keep in mind it is a joke!) What are the reasons to not have non-const get_error_info? I haven't look into implementation but I guess it requires almost no work at all to add (and maintain) it.
In fact yesterday I went ahead and implemented it on my system, seems fine. I'll do some more testing and I'll commit it to trunk soon. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode