From: csrabak@dce03.ipt.br (Cesar Scarpini Rabak) Subject: Re: FW: Re: wxwin port 11 Nov 1996 12:22:44 -0800 Sender: daemon@cygnus.com Approved: cygnus.gnu-win32@cygnus.com Distribution: cygnus Message-ID: <1.5.4.16.19961111125433.379f9d86.cygnus.gnu-win32@dmeasc.rc.ipt.br> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Sender: csrabak@dmeasc.rc.ipt.br X-Mailer: Windows Eudora Light Version 1.5.4 (16) Original-To: Fabio Somenzi , gnu-win32@cygnus.com Original-Sender: owner-gnu-win32@cygnus.com At 04:19 10/11/96 -0700, Fabio Somenzi wrote: >->Does anyone have any input on why 16 bytes from gnu-win32 and >->14 for other compiler > >I believe it's because gcc enforces alignment. The two extra bytes are >not used. I've seen it done by other compilers as well. > >In some applications alignment is important. For instance, a 16-byte >structure can be aligned with the boundaries of the cache lines. > >Alignment may also have to do with the memory manager (reducing the >number of buckets,) but I'm not familiar with this aspect of gcc. > >There may be a gcc option to enforce structure packing, but memory may >fail me here. > It is not an option for the command line of gcc but rather an extension of C language by GNU. Look in the docs for: "__attribute__((packed))" [snipped] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cesar Scarpini Rabak E-mail: csrabak@ipt.br DME/ASC Phone: 55-11-268-35221Ext.350 IPT - Instituto de Pesquisas Tecnologicas Fax: 55-11-268-5996 Av. Prof. Almeida Prado, 532. Sao Paulo - SP 05508-901 BRAZIL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - For help on using this list, send a message to "gnu-win32-request@cygnus.com" with one line of text: "help".