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From: Cedric Roux <cedric.roux@acri-st.fr>
To: gcc-help@gcc.gnu.org
Subject: Re: Need help using gcc in command line mode.
Date: Mon, 21 Dec 2009 09:22:00 -0000	[thread overview]
Message-ID: <4B2F325E.10709@acri-st.fr> (raw)
In-Reply-To: <4B2D069D.9080100@htw-berlin.de>

Thomas Martitz wrote:
> Try appending __attribute__((packed)) after the closing } of the structs 
> in question. That should disable padding.
> 
> Furthermore I recommend using int32_t instead of long, since long is 8 
> bytes on 64-bit Linux systems (hence your code wouldn't work on those).
> 
> Best regards.

You can also compile with -fpack-struct
(see "man gcc")

But may I suggest that you read your file byte by byte
and feed the structures by reconstructing data with those
bytes (like "x = c1 | (c2 << 8) | (c3 << 16)" or something)?
It is the most portable solution and if your
programs don't spend all of their time in reading these
headers then there is no need to "optimize." (And you
won't waste a lot of time debugging in that direction...)

Regards,
Cédric.

  reply	other threads:[~2009-12-21  8:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-19 17:00 Gene Creighton
2009-12-19 17:09 ` Thomas Martitz
2009-12-21  9:22   ` Cedric Roux [this message]
2009-12-21 17:00     ` Andrew Haley

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