tom@tcom.stc.co.uk (Tom Sanders) (10/19/89)
Unix System V, Release 3.1
--------------------------
I am trying to write a shell script which will set up a set of tty
options and exec a process. Simple enough, I thought, but I get
the error message:
stty: : Invalid argument
Briefly, the problem has been traced to a number of options on the stty
command. For example,
stty igncr < /dev/tty6
will produce the error message. However,
stty -igncr < /dev/tty6
is OK!! Other options which behave this way are isig, icanon, olcuc
and more. The negative form is OK, the positive form not. If the
printer scheduler interface scripts can do it, why cant I?
Any info gratefully received.
Regards,
Tom Sanders
--
Tom Sanders <tom@tcom.stc.co.uk>
STC Telecomms, Oakleigh Rd South, London N11 1HB UK.tom@tcom.stc.co.uk (Tom Sanders) (10/26/89)
In article <1845@bute.tcom.stc.co.uk> tom@tcom.stc.co.uk I wrote:
#Unix System V, Release 3.1
#--------------------------
#
#I am trying to write a shell script which will set up a set of tty
#options and exec a process. Simple enough, I thought, but I get
#the error message:
#
# stty: : Invalid argument
#
#Briefly, the problem has been traced to a number of options on the stty
#command. For example,
#
# stty igncr < /dev/tty6
#
#will produce the error message. However,
#
# stty -igncr < /dev/tty6
#
#is OK!! Other options which behave this way are isig, icanon, olcuc
#and more. The negative form is OK, the positive form not. If the
#printer scheduler interface scripts can do it, why cant I?
#
#Any info gratefully received.
After a stunning response (0 follow-ups, 0 replies :-)) I discovered with
a little help that the options which were failing are implemented by a
module in the Stream sitting on the tty driver. Until that module has been
pushed on to the Stream (with ioctl) only the hardware related options are
supported, things like character mapping and signal handling are not.
When opening a tty device not used by the system for logins, the module
is not present. Just thought you might like to know...
Regards,
Tom
--
Tom Sanders <tom@tcom.stc.co.uk>
STC Telecomms, Oakleigh Rd South, London N11 1HB UK.