[Boost-users] Re: unordered_map has no lower_bound?

From: Daniel James (daniel_at_[hidden])
Date: 2005-04-03 16:27:56

> Martin Wartens wrote:
>> PS: there is a small problem in hash_table.hpp causing a warning in VC7.1
>> line 278 should be:
>> return (*prev_ptr)!=0;
>> instead of
>> return *prev_ptr;

Ah, I just found out why I didn't do this before - prev_ptr might be a 
pointer object (depending on the allocator), so the correct line is:

return (*prev_ptr) != link_ptr();

Which can potentially be inefficient. I think the best thing to do is to 
use a pragma to disable the warning, or maybe:

     return static_cast<bool>(*prev_ptr);

or:

     return boost::implicit_cast<bool>(*prev_ptr);

would work.

Daniel