2.3.10. - Keyboard Interrupts
On UNIX systems, two different asynchronous
signals can be sent from the keyboard to programs.
These signals are
interrupt
and
quit.
A
^C
is usually used to generate the
interrupt
signal.
A
^\
generates a
quit
on many versions of UNIX, although
^V
is used on some others.
The control key assignments are arbitrary and can be
changed using the
stty
command from the UNIX shell.
A common problem for new users is that their default UNIX
environment
has either no keys or archaic keys assigned to these signals.
To display the current key assignments
on BSD-type systems, type
stty everything
from the shell.
On System V systems, type
stty -a.
With spec, the
interrupt
key
halts all
activity, including asynchronous motor motion or counting,
and closes all command files.
All output files and devices (except
log,
dlog
and
elog
files) are closed.
On keyboard interrupts (and command and syntax errors),
cleanup
macros, as described below may be run.
Typing the
quit
character
will asynchronously terminate spec
without saving the user's state.
However, if motors are moving,
the program will wait for them to halt and then update the
settings
file.
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