Re: [Boost-users] How to use property_map?

Subject: Re: [Boost-users] How to use property_map?
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2010-04-07 22:00:54

On Thu, 8 Apr 2010, Yaohua Xiong wrote:

> Hi, Jeremiah. Thanks for your reply.
>
>> The declaration "PMap map();" declares a function named "map" that returns
>> an object of type "PMap". Â Just use the original form "PMap map;" if you
>> want to declare an actual map.
>
> You are right. What a stupid mistake I make, probably I've been
> writing Python for too long time :-). As for the original form do you
> have some speculation on why it's crashing?
>
> After I surf on the Internet for a while, I found a solution to the
> crashing problem by change the program into:
>
> #include <iostream>
> #include <map>
> #include <string>
> #include <boost/property_map/property_map.hpp>
> using std::string;
> using boost::put;
> using boost::get;
>
> int main()
> {
> typedef std::map<std::string, int> Map;
> typedef boost::associative_property_map<Map> PMap;
>
> Map tmp;
> PMap map(tmp);
> put(map, string("acc"), 1);
> get(map, string("acc"));
>
> return EXIT_SUCCESS;
> }

The associative_property_map just contains a reference to a container, not 
an actual container.  Look at 
<URL:http://www.boost.org/doc/libs/1_42_0/libs/property_map/doc/associative_property_map.html> 
for more information (see the top paragraph).

-- Jeremiah Willcock