Message-ID: <3E2726AB.9030704@earthlink.net>
From: Martin Ambuhl <mambuhl AT earthlink DOT net>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01
X-Accept-Language: en-us, en, de, fr, ru, el, zh
MIME-Version: 1.0
Newsgroups: comp.os.msdos.djgpp
Subject: Re: sizeof(struct x) doesn't compile -- how to do it ?
References: <b07318$3eg$1 AT news DOT online DOT de>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 49
Date: Thu, 16 Jan 2003 21:40:16 GMT
NNTP-Posting-Host: 67.210.12.88
X-Complaints-To: abuse AT earthlink DOT net
X-Trace: newsread2.prod.itd.earthlink.net 1042753216 67.210.12.88 (Thu, 16 Jan 2003 13:40:16 PST)
NNTP-Posting-Date: Thu, 16 Jan 2003 13:40:16 PST
Organization: EarthLink Inc. -- http://www.EarthLink.net
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Lars Hansen wrote:
> #include "stdlib.h"
> 
> struct x
>  {
>   double x;
>  };
> 
> int main()
>  {
>   x* n=malloc(2*sizeof(struct x));
>  }
> 
> 
> produces the following compiler error message:
> 
> test.c: In function `main':
> test.c:10: `x' undeclared (first use in this function)
> test.c:10: (Each undeclared identifier is reported only once
> test.c:10: for each function it appears in.)
> test.c:10: `n' undeclared (first use in this function)
> 
> 
> So how do I get the size of structs with djgpp?
#include <stdlib.h>

struct x
{
     double x;
};

int main()
{
     struct x *n = malloc(2 * sizeof(struct x));
}

> 
> And also: if i have an array of a struct with several elements how can i know
> at which byte an element of the nth struct is in that array with djgpp (eg
> after writing a struct array to file and then loading this data without
> knowing how to "synchronize" djgpps compiler struct array generation and
> saving and an other compilers array struct generation and loading means one
> best knows the byte position (and length))

Lookup offsetof()