Mail Archives: djgpp/1997/10/13/08:36:21
On Friday, I wrote:
>Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> 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.
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| Alex Holden- Electronics student, computer |
| programmer, caver, and Land Rover nut. |
| http://www.geocities.com/CapeCanaveral/Lab/1532/ |
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