[Boost-users] [unordered_map] Trying to understand some errors

Subject: [Boost-users] [unordered_map] Trying to understand some errors
From: Craig Longman (craigl_at_[hidden])
Date: 2011-05-03 01:04:16

I'm using VS v9, just in case that matters in this case.

I'm :

     using namespace std;
     using namespace boost;

     unordered_map< string, uint32_t > xrf1;
     unordered_map< string, uint32_t >::const_iterator& iter = 
xrf1.find( "hello" );

This is something I've used many times with the other containers (well, 
std::map at least), but here I'm getting a conversion error.  This is 
resolved by either removing the reference marker, or removing the const 
qualifier.

Can someone explain this please?  I'd always thought that applying const 
was easily done, and if so, then a reference should be sufficient, 
right?  Unless the const cast is marked as explicit somehow?

And as a side(ish) question, is there any real need to worry about have 
an object versus reference to something like an iterator?  I've always 
tried to use references where I can, but I wonder if I should "just say 
no" and use regular objects from now on?

Thanks,

-- 
Craig Longman
If it's not *signed* by me, then please don't assume it *is* from me.