Messages in this thread |  | | Date | Fri, 11 May 2001 08:25:16 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: Not a typewriter |
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On Thu, 10 May 2001, H. Peter Anvin wrote:
> Wayne.Brown@altec.com wrote: > > > > On 05/10/2001 at 05:38:32 PM hpa@transmeta.com (H. Peter Anvin) wrote: > > > > >Sounds like someone has just clarified what the heck it means. "tty" > > >and "typewriter" aren't exactly the same thing (even though "tty" > > >stands for "teletypewriter" it has come to mean something completely > > >different in a Unix context)... "not a typewriter" is just a > > >completely confusing error message for the uninitiated. > > > > I disagree. "Not a typewriter" is part of Unix tradition, and ought to be > > retained as a historical reference. It's also an opportunity for "the > > uninitiated" to learn a little more and move a little closer to becoming "the > > initiated." > > > > Nowhere else in Unix is a "tty" referred to as a "typewriter". "Not a > tty" is one thing; "Not a typewriter" is just plain misleading. >
I was told that "Not a typewriter" was a catch-all for a screw-up. It was to advise that it wasn't a typewriter keyboard you were hacking at, where you could enter anything.
Over the years, I have used ENOTTY as a temporary return-code from drivers and library procedures so I could tell what procedure was returning an error. For instance, if you have a number of calls that return ETIME, during testing it would be nice to see what routine timed out. I was quite surprised to find out that perror() was printing an error string that none of my procedures were thought to have generated. Then I wrote:
#include <stdio.h> #include <errno.h> main() { errno = ENOTTY; perror(""); }
So "Not a typewriter" has been depreciated (deprecated?). The text in the header file probably should be changed to show this.
Cheers, Dick Johnson
Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).
"Memory is like gasoline. You use it up when you are running. Of course you get it all back when you reboot..."; Actual explanation obtained from the Micro$oft help desk.
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