Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!ut-sally!husc6!think!ames!oliveb!sun!gorodish!guy From: guy%gorodish@Sun.COM (Guy Harris) Newsgroups: comp.lang.c Subject: Re: Inline assembler; a quiz (long; sorry) Message-ID: <22887@sun.uucp> Date: Wed, 8-Jul-87 08:14:42 EDT Article-I.D.: sun.22887 Posted: Wed Jul 8 08:14:42 1987 Date-Received: Sat, 11-Jul-87 03:35:46 EDT References: <608@zen.UUCP> <2299@hoptoad.uucp> <21211@sun.uucp> <830@omepd> <4793@columbia.UUCP> Sender: news@sun.uucp Lines: 30 > The point I'm trying to make is that on Unix the programmer doesn't > have to worry about the assembler "glue" thats being used. Not only > can a programmer use a system call in the same manner as a function > call, And the point that many others have been making is that this is in NO WAY unique to UNIX; other OSes do the same thing. Even if the OS doesn't provide assembler wrappers for system calls as part of its standard library (or if the C compiler doesn't do so), these wrappers can be written *without* recourse to "asm". The original posting seemed to imply that UNIX was somehow unique in that you could get away without "asm", but that C implementations on other OSes couldn't; this isn't true in general, because the same techniques used on UNIX can be used on those other OSes. > but can even get an understanding of what the system call is > doing (what tables is it modifying etc.) because the guts of it > are also written in 'C'. Well, first of all, you can't do that if you don't have source, and many - probably most - UNIX sites don't have source. Second, I wouldn't go so far as to say that *any* programmer could get an understanding of what the system call is doing just by looking at the source code; some stuff in the system is very complex and subtle, and won't be obvious without a LOT of study. Third of all, UNIX is NOT the only OS not entirely written in assembler. And fourth, this has nothing to do with what the original discussion was about, anyway. Guy Harris {ihnp4, decvax, seismo, decwrl, ...}!sun!guy guy@sun.com