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Date: Fri, 08 Feb 2002 10:10:42 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
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To: Eric Rudd <rudd AT cyberoptics DOT com>
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In-reply-to: <3C629769.AEAFB611@cyberoptics.com> (message from Eric Rudd on
	Thu, 07 Feb 2002 09:04:09 -0600)
Subject: Re: Alignment problem
References:  <3C629769 DOT AEAFB611 AT cyberoptics DOT com>
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> Date: Thu, 07 Feb 2002 09:04:09 -0600
> From: Eric Rudd <rudd AT cyberoptics DOT com>
> Newsgroups: comp.os.msdos.djgpp

[Note that I redirected this to djgopp-workers.]

> int main(void) {
>    void *ptr;
> 
>    ptr = malloc(1024);
>    if (((int) ptr) & 7) {
>       printf(" ptr %p not 8-byte aligned.\n", ptr);
>    } else {
>       printf(" ptr %p     8-byte aligned.\n", ptr);
>    }
>    free(ptr);
>    return 0;
> }
> 
> I get output like
> 
>  ptr 8f4e4 not 8-byte aligned.
> 
> about half the time.

I cannot reproduce this on Windows, but I do get 4-byte aligned
pointers on MS-DOS.

> I thought that this alignment problem had been solved in gcc 2.95 and
> binutils 2.9.1.

This has nothing to do with the compiler or Binutils, I think: malloc
gets memory from the DPMI server, and then subdivides them into
chunks.  The alignment of data that's on the heap should be malloc's
job.

It sounds like malloc doesn't do that, though.  Can someone tell where
in malloc is the code that should have produced aligned pointers?  Am
I missing something?

Or are you saying that the whole data segment is unaligned?