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From: Joel Brobecker <brobecker@adacore.com>
To: Hui Zhu <teawater@gmail.com>
Cc: Michael Snyder <msnyder@vmware.com>,
		"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Subject: Re: [RFA] record.c - save some memory in record log.
Date: Sun, 18 Oct 2009 16:10:00 -0000	[thread overview]
Message-ID: <20091018161019.GM5272@adacore.com> (raw)
In-Reply-To: <daef60380910171852t3261114fscb6ee9d4d82fd005@mail.gmail.com>

> But I think:

Note that I was just idly mentioning a trick I saw us use in the past,
but it's definitely ok if you guys think it's a bad idea.

> +  union
> +  {
> +    gdb_byte *ptr;
> +    gdb_byte buf[2 * sizeof (gdb_byte *)];
> 
> Make the size of buf more clear.

The problem with this approach is that the size of the union is the
maximum of all its components.  So the size of your union is always
going to be 8/16 bytes, depending on whether addresses are 4 or 8 bytes.
Unless buf was meant to be a 2-bytes buffer, then the size is always
going to be 4 bytes.

With the trick I provided, the size is always going to be exactly as
much as you need.  But, like I said, it's not exactly super clean...

-- 
Joel


  reply	other threads:[~2009-10-18 16:10 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-15 17:59 Michael Snyder
2009-10-15 19:17 ` Joel Brobecker
2009-10-18  1:53   ` Hui Zhu
2009-10-18 16:10     ` Joel Brobecker [this message]
2009-10-18 16:14       ` Michael Snyder
2009-10-18  1:50 ` Hui Zhu
2009-10-18  3:56   ` Michael Snyder
2009-10-18  4:46     ` Hui Zhu
2009-10-18 16:11       ` Michael Snyder

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