[hylafax-devel] Re: /bin/stty: standard input: unable to perform all requested operations

[Darren Nickerson <darren@dazza.org>]

>>>>> On Sun, 19 Mar 2000, "Phil" == Phil Watkinson wrote:

  Phil> Removing line 773 of faxaddmodem.sh works for me - tested with
  Phil> Multitech and SupraExpress modems on a RedHat 6.0 clone Linux
  Phil> distribution. The stty source (part of the sh-utils rpm) hasn't changed
  Phil> for years so I suspect the Linux 2.2 kernel has introduced this
  Phil> message.

Hiya Phil ;-)

It's the 'stty 0' which fails now. Previously:

	[root@fax /root]# cat /etc/issue
	
	Red Hat Linux release 4.2 (Biltmore)
	Kernel 2.0.30 on an i586

	[root@fax /root]# stty --version
	stty (GNU sh-utils) 1.16
	[root@fax /root]# stty 0
	[root@fax /root]# 

whereas now we see:

	[root@ducent uucp]# cat /etc/issue
	
	Red Hat Linux release 6.1 (Cartman)
	Kernel 2.2.14pre11 on a 2-processor i686
	
	[root@ducent uucp]# stty --version
	stty (GNU sh-utils) 2.0
	Written by David MacKenzie.

	[root@ducent uucp]# stty 0
	stty: standard input: unable to perform all requested operations
	[root@ducent uucp]# 

The original author was apparently wanting a system-independent way of
resetting the modem . . . hanging up the line with stty seemed to do the trick. Until now :-(

The man page for the working version says of the numeric argument to stty:

       Special settings:

       N      Set the input and output speeds to N.  N can be one
              of: 0 50 75 110 134 134.5 150 200 300 600 1200 1800
              2400 4800 9600 19200 38400 exta extb.  exta is  the
              same  as 19200; extb is the same as 38400.  0 hangs   <--------
              up the line if -clocal is set.                        <--------

IRIX 6.4 says:

   Control Modes
     0         hang up phone line immediately.

Whereas the current 

   Special settings:
       N      set the input and output speeds to N bauds

and no mention of the reset special case if N=0.

There's an interesting discussion of stty behaving this way in:

http://x36.deja.com/getdoc.xp?AN=445335138&CONTEXT=953500619.1000276005&hitnum=20

Aside from removing the call in the case of modern linux distros (ugly) can anyone propose a solution? Is the reset even needed? The faxaddmodem script says:

	#
	# Send each command in SendString to the modem and collect
	# the result in $OUT.  Read this very carefully.  It's got
	# a lot of magic in it!
	#
Magic . . . man I hate magic. Magic is for smart ppl.

-Darren


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