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Re: distributing data across a structure (new to c please help)

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nwdpil <mkeput@gmail.com> writes:

> the ulimate goal is to read the MZ header from a binary windows pe
> file, which is simple enough. anyway the theory goes (and this is the
> bit i dont understand im new to c programming) i memcpy the data from
> the file ACROSS a struct. is this possible? i dont understand how to
> initialise and manipulate the struct. can i copy a set of data that is
> 16bytes long, to a struct with two 8byte children and will memcpy then
> distribute the data for me if i pass it pointers?
>
> it sounds easy but im really struggling to get to grips with
> it. anyway heres a simple c program i wrote to demonstrate the
> concept. it fails with the error Run-Time Check Failure #3 - The
> variable 'x' is being used without being initialized.
>
> for example i should be able to access string "00004444" with x->b; and "eeeeffff" with x->bb;
>
> im on windows running visual c++ 2010 express, although im coding
> purely in c because i never saw the point in object orientated
> programming.
>
> help please?
>
> [code]
> // pointblank.c : Defines the entry point for the console application.
> //
>
> #include "stdafx.h"
> #include "stdio.h"
> #include "stdlib.h"
> #include "string.h"
>
> typedef struct _test {
> 	char b[8];
> 	char bb[8];
> }; test, *ptest;

Also, do not forget about C compiler may align all struct members by 4
bytes on x86 and 8 bytes on Win64. 
Since Windows PE file fields are all differently sized and this is very
important, please consult "pack" pragma:
http://msdn.microsoft.com/en-us/library/2e70t5y1(v=vs.80).aspx
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distributing data across a structure (new to c please help) nwdpil <mkeput@gmail.com> - 2012-08-09 20:32 -0500
  Re: distributing data across a structure (new to c please help) James Kuyper <jameskuyper@verizon.net> - 2012-08-10 00:43 -0500
  Re: distributing data across a structure (new to c please help) Dennis Yurichev <dennis_mailing_lists@conus.info> - 2012-08-20 14:17 -0500
    Re: distributing data across a structure (new to c please help) Keith Thompson <kst-u@mib.org> - 2012-08-20 22:10 -0500
    Re: distributing data across a structure (new to c please help) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-08-20 22:11 -0500

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