Re: [Boost-users] How to obtain vertex pointer (not descriptor) of vertex created with add_vertex.

From: Nat Goodspeed (nat_at_[hidden])
Date: 2008-05-14 12:35:48

Ananth Durbha wrote:

>    I am trying to modify a set of file parser callback functions (for a 
> custom file format) to populate a  Boost graph. The callbacks provide a 
> (void*) pointer style parameter passing. But Boost graph method 
> add_vertex(graph) will return a vertex descriptor. How do I obtain the 
> pointer information for this newly added vertex so that the pointer can 
> be cast as (void*) and passed to the appropriate call back?

If you're writing the code that calls the callback, what about something 
like this (untested):

struct CallbackData
{
     /* vertex descriptor type */ vertex_desc;
};

...

     CallbackData cdata;
     cdata.vertex_desc = add_vertex(...);
     (*callback)(reinterpret_cast<void*>(&cdata));

Then, inside your callback:

void my_callback(void* data)
{
     CallbackData* pdata = reinterpret_cast<CallbackData*>(data);
     /* ... use pdata->vertex_desc ... */
}

? If that's not the scenario you have in mind, then please explain more 
clearly.