Re: [Boost-users] [Serialization] Load an object from the base pointer

Subject: Re: [Boost-users] [Serialization] Load an object from the base pointer
From: Robert Ramey (ramey_at_[hidden])
Date: 2009-03-05 11:10:29

This is all done internally by the library.  Feel free to browse through the source and documentation.

Robert Ramey
  "Ryan Fowler" <Ryan.Fowler_at_[hidden]> wrote in message news:1C50BA0DCB34A24E9C8ABA96570EF18F073F5212_at_LONSMSXM06.emea.ime.reuters.com...
  I've seen the following:

   

  main(){

      ...

      base *b;

      ...

      ar & b; 

  }

   

  But that doesn't quite help me.  All of our objects come from a memory pool and I either need to know ahead of time which object to allocate or I need to pass an allocator to the archive so that it can get the memory from the pool.

   

  Are either of these possible?  Also, in the above example, how does the archive allocate the memory for 'b'?  Does it use new?  Or does it have it's own pre-allocated store?

   

  Thanks,

  Ryan

   

  From: boost-users-bounces_at_[hidden] [mailto:boost-users-bounces_at_[hidden]] On Behalf Of Robert Ramey
  Sent: 04 March 2009 17:30
  To: boost-users_at_[hidden]
  Subject: Re: [Boost-users] [Serialization] Load an object from the base pointer

   

  This is explained in the documentation and illustrated by the demos and tests.

   

  In fact, you can even build a progam which will be able to de-serialize types included

  in DLLS which have yet to be created.

   

  Robert Ramey

    "Ryan Fowler" <Ryan.Fowler_at_[hidden]> wrote in message news:1C50BA0DCB34A24E9C8ABA96570EF18F073F5211_at_LONSMSXM06.emea.ime.reuters.com...

    Hi,

     

    How can I read in a from a stream when I don't know the exact type I will be getting?  All objects I receive will derive from the same base class, but I won't know when I receive the stream what the derived type will be and therefore I can't create it in advance (like in the docs).

     

    class base

    {

    .

    }

     

    class derived1 : public base

    {

    .

    }

     

    class derived2 : public base

    {

    .

    }

     

    int main()

    {

        // Get a stream from somewhere

        boost::archive::binary_iarchive ia( instream );

     

        base b0;

        derived1 d1;

        derived2 d2;

        is >> // derived1 or derived2???

    }

     

    Ryan Fowler
    Software Engineer

    Thomson Reuters 

    Phone: [phone]

    ryan.fowler_at_[hidden]
    thomsonreuters.com

    This email was sent to you by Thomson Reuters, the global news and information company.
    Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Thomson Reuters. 

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