Re: [Boost-users] Boost.Interprocess accessing an unordered_map in shared memory.

Subject: Re: [Boost-users] Boost.Interprocess accessing an unordered_map in shared memory.
From: Nat Linden (nat_at_[hidden])
Date: 2013-03-12 09:19:11

On Tue, Mar 12, 2013 at 12:43 AM, <lazylabs_at_[hidden]> wrote:

> On Tue, Mar 12, 2013 at 2:21 AM, Ion Gaztañaga <igaztanaga_at_[hidden]>
> wrote:

> > El 11/03/2013 13:20, lazylabs_at_[hidden] escribió:
>
> >> However, I would prefer to do this with a std::string, which results
> >> in compilation errors:
> >>
> >> persons->at(std::string("H")).print();
> >>
> >> Is it possible to write the above statement, i.e. accessing the map
> >> allocated in shared memory with std::string?

> > No, as the key_type is not std::string. It's a bit ugly but to fix this
> > has no easy fix.

> As I understand, the reason why we cannot lookup ShmemString with
> std::string is because of the template argument, which I have given
> while creating the unordered_map:
>
>                 std::equal_to<KeyType>,
>
> Just guessing, if something can be done here?

It seems to me that within the last year or so another person on this
mailing list (who had his own local idiosyncratic string type) was
asking about passing std::string or const char* key arguments for map
lookup. I don't even think it was specific to Interprocess. I believe
he was proposing string comparators accepting range-of-characters
rather than a specific string type.

Sorry for vagueness; I don't have time to search for it myself...