From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Marmond Subject: Re: A question on cat.asm from asmutils-0.17 Date: Tue, 18 Nov 2003 08:38:16 +0100 Sender: linux-assembly-owner@vger.kernel.org Message-ID: <3FB9CC68.9090802@eprocess.fr> References: <3FB9986D.60709@cbf.chinese2000.net> Reply-To: fmarmond@eprocess.fr Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3FB9986D.60709@cbf.chinese2000.net> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Lawrence Cc: linux-assembly@vger.kernel.org Hi, One of the goal of asmutils is to be as small as possible. So, any 'non-very-necessary' things are commented out to save place. In Linux, when you open file, a file descriptor is stored in the process memory. When you release the process, the system close all its opened files. So, what is done in cat.asm is *not* a nice thing (every thing that is opened must in theory be closed) but it is a good way to reduce code size (from few bytes, but it is the power of assembly) without breaking anything. hope it helps Fred Lawrence wrote: >Hi All, > >I'm trying to get acquintant with Linux assembly language by studying >the asm code found in asmutils. > >While studying cat.asm, I discover that every time a file is opened >using sys_open, there is no correspondent sys_close to it. (The codes >were marked). > >I would like to ask if this is an legitimate way to open a file without >closing it under Linux, or just a convenient way to let the >shell/kernel(I'm not sure...) to close the file for us when cat is >finished. For my experience on MS-DOS assembly, I must close an >opened-file, or otherwise I'll encounter an out of file handle error. > >Thanks and Regards, >Lawrence > >- >To unsubscribe from this list: send the line "unsubscribe linux-assembly" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html > > >