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Section A:
A.5.5. BREAK Characters
General Introduction
*******************************
*
Using the Keyboard
*
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Typing
one of these characters cause the current program to be aborted.
They
must
be
entered as the first character of
an
input
line.
The
standard BREAK character is AC (Control-C).
Furthermore, A[ or (ESCAPE>
is another commonly used BREAK character.
By means of =>
$CONFIG,
you
can
define any second BREAK character you prefer.
Whenever EOS
recog-
nizes
a
BREAK
character,
the following message is displayed
on
the
screen:
<Restart>
To
user progams,
EOS offers a facility
to suppress the recognition of
BREAK charactersi
so do not be surprised when under certain circumstan-
ces,
typing a BREAK character has no effect[
Most EOS
utilities,
for
example,
ignore
BREAK characters or admit them only at certain
situa-
tions.
A.S.6. Suspending Screen Output
Many programs do their CRT screen output at such a tremendous speed that
no
normally
gifted man can follow up in
reading.
Therefore,
it
was
necessary to define a specific character to stop screen output.
This is
the
As (Control-S).
character.
When
you press AS,
screen output is immediately suspended.
After output has stopped, you can choose from several possibilities:
AQ (Control-Q) resumes screen output.
AC (Control-C) or another BREAK character aborts the program.
Ap
(Control-P) switches
the printer on.
It then runs parallel
to
the
screen until it is switched off by another
AP,
or by the SHELL command LIST OFF.
Here too,
it shall not remain a secret that a number of programs simply
ingpore Control-S. The EOS utility => $TYPE is an example of this class,
It
cannot be suspended by typing Control-S,
for the very simple reason
that it stops by itself after it has filled a screen page.
EOS User's manual
Daeumling & Zimmermann
Page 19
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