From: Vic <tudor AT cam DOT org>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: OT: how can I declare and use struct with as.exe ?
Date: Sun, 24 Jan 1999 12:49:42 -0500
Organization: Communications Accessibles Montreal, Quebec Canada
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To: djgpp AT delorie DOT com
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Martin Str|mberg wrote:
> 
> Wolfy (k6 AT lycosmail DOT com) wrote:
> : I know how to declare and use struct with masm but with gnu as I am in
> : trouble; can anyone help me ?
> 
> Declare a struct in C, compile with "-S" and look at the output?

doesn`t help much. the following C code

struct t
{
int a;
long b;
long long c;
};

struct t out_main;

main()
{
out_main.a=5;
out_main.b=654;
out_main.c=13466;

}

gives this:

        .file   "a.c"
gcc2_compiled.:
___gnu_compiled_c:
.comm _out_main,16
.text
        .p2align 2
.globl _main
_main:
        pushl %ebp
        movl %esp,%ebp
        movl $5,_out_main
        movl $654,_out_main+4
        movl $13466,_out_main+8
        movl $0,_out_main+12
        leave
        ret


The way it declares a struct, only when it is global (if it`s in a
fuction it uses the stack) is by using 

.comm name,length:

.comm _out_main,16 declares an out_main struct 16 bytes long.
you access the members by their offset in the struct.