Re: [Boost-users] trying to build custom property_map

Subject: Re: [Boost-users] trying to build custom property_map
From: Sandeep Gupta (gupta.sandeep_at_[hidden])
Date: 2010-04-01 15:39:19

On Thu, Apr 1, 2010 at 5:17 AM, Jeremiah Willcock <jewillco_at_[hidden]>wrote:

> On Wed, 31 Mar 2010, Sandeep Gupta wrote:
>
>
>>
>>
>>            Hi,
>>             I created a  simple property_map as follows:
>>
>>            struct VecMap
>>            {
>>             typedef int value_type;
>>
>>             typedef int key_type;
>>             typedef  read_write_property_map_tag category;
>>
>>             typedef int* reference;
>>             std::vector<int> vec_store;
>>
>>            };
>>            void put(VecMap& rmap, int key, int val)
>>
>>            {
>>             rmap.vec_store[key] = val;
>>
>>            }
>>            int get(VecMap& rmap, int key)
>>
>>            {
>>             return rmap.vec_store[key];
>>
>>            }
>>            /// End code
>>            The compiler gcc-4.4.1 against latest boost-trunk gives
>> errorerror: no type named value_type in struct
>>            boost::property_traits<VecMap>
>>            The code however compiles fine with boost_1_40. Please take a
>> look.
>>            The full code is available here http://codepad.org/KtmbXkLa
>>
>>
>> I tried the code you posted (at codepad) with GCC 3.4, 4.1, and 4.4.0 and
>> did not receive an error.  Note that in the trunk, the
>> property_map header file is <boost/property_map/property_map.hpp>.
>>
>> -
>>
>> The posted code works with earlier version of boost. However when I change
>> the header to boost/property_map/property_map.hpp and use
>> boost-trunk that it start giving errors.
>> I compiled against gcc 4.4.1, 4.4 and 4.2. It gives the same  error for
>> all the three.
>>
>
> I changed the code to use the new header file and compiled against the
> trunk and still don't get any errors.  What errors are you seeing (i.e., the
> full gcc output)?
>
>
It seems that the error occurs when I don't define   "typedef int&
reference" for the property map class.  The confusing part is that when I
compile with boost_1_42 I get the error

boost_1_42_0/boost/property_map/property_map.hpp:33: error: no type named
'reference' in 'struct VecMap'

Which is expected. However, If I compile against the trunk I get undefined
value_type error instead of undefined reference error.

boost-trunk/boost/pending/disjoint_sets.hpp:65: error: no type named
'value_type' in 'struct boost::property_traits<VecMap>'

Something surely is amiss here. Most likely in the disjoint_sets.hpp, I
believe.

Thanks
-Sandeep