Method for making a variable size struct
I need to craft a packet that has a header, a trailer, and a variable length payload field.  So far I have been using a vector for the payload so my struct is set up like this:

    struct a_struct{
     hdr a_hdr;
     vector<unsigned int> a_vector;
     tr a_tr;
    };

When I try to access members of the vector I get a seg fault and a sizeof of an entire structs give me 32 (after I've added about 100 elements to the vector.

Is this a good approach?  What is better?

I found this post
http://stackoverflow.com/questions/688471/variable-sized-struct-c
He was using a char array, and I'm using a vector though.
Method for making a variable size struct
===

I need to craft a packet that has a header, a trailer, and a variable length payload field.  So far I have been using a vector for the payload so my struct is set up like this:

    struct a_struct{
     hdr a_hdr;
     vector<unsigned int> a_vector;
     tr a_tr;
    };

When I try to access members of the vector I get a seg fault and a sizeof of an entire structs give me 32 (after I've added about 100 elements to the vector.

Is this a good approach?  What is better?

I found this post
http://stackoverflow.com/questions/688471/variable-sized-struct-c
He was using a char array, and I'm using a vector though.