Message-ID: <19971013123422.14430.qmail@hotmail.com> From: "Alex Holden" To: djgpp AT delorie DOT com Subject: Re: Writing code for both DJGPP and Linux. Content-Type: text/plain Date: Mon, 13 Oct 1997 05:34:20 PDT Precedence: bulk On Friday, I wrote: >Eli Zaretskii wrote: >>On Tue, 7 Oct 1997, Hartmut Schirmer wrote: >> >>> Isolate your serial routines in one source for for DJGPP and one >>> for Linux. For Unix (incl. Linux) serial port programming see >>> >>> http://www.easysw.com/~mike/serial/ >> >>I'd like to suggest another approach here? Since on Linux, the >>``correct'' >>way of accessing devices is through `ioctl' and "/dev/ttyX", why not >>add this to DJGPP? It shouldn't be too hard: all Alex has to do is >>to >>use the DJGPP Filesystem Extension feature. Using it, Alex will >need >>to install a handler for several functions, like `open', `close', >>`ioctl', `lseek', `read' and `write', and when they reference >>"/dev/ttyX" file, redirect them to some serial code (e.g., Bills >>`bcserio' package which is available from the DJGPP archives). On >>Linux, these calls will just work as usual. >> >>That way, Alex gets a portable program, while DJGPP gets >>POSIX-compliant serial port support. And they all live happily ever >>after... >Hmm, sounds an interesting idea. I'll have a play with it over the >weekend and let you know if I think I'll be able to do it on Monday >(I don't have Internet access at home). If anyone else has any >comments on whether this is feasible, a good idea, a Bad Idea(tm), or >whatever, I'd like to hear from them. >Thanks, Alex. Okay, after spending the weekend immersed in DPMI, assembly code, man pages, info pages, LIBC source, Linux kernel source, etc. I think I can say that Eli was being a bit optimistic when he said it shouldn't be too hard. But, what the heck, I'm going to have a go anyway. I would still welcome advice from anyone who knows how to use the DJGPP file system extensions. The other main thing I have not been able to track down is a proper spec on just how serial communication is supposed to happen under Unix. I have the Linux serial programming howto, but after reading it, I was just more confused than when I started. I had a look at the tutorial at easysw.com (see above for the address), but it is not available for direct download (it's in a fancy frames arrangement so you can't simply save it from the browser). Also, the guy does not give his email address, and when I tried to send one to him C/O the site's webmaster, it turned out they wouldn't accept email from hotmail. How they expect to get any business without giving out their Email I don't know! Thanks again, Alex. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | Alex Holden- Electronics student, computer | | programmer, caver, and Land Rover nut. | | http://www.geocities.com/CapeCanaveral/Lab/1532/ | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com