SunOS Clear Screen

SunOS Clear Screen

[Perry K. Lund]

Sorry for asking this question again, but at the time I did not need to
think about it.

Where can I find information on accomplishing a clear screen command for
Ada.  I am running GNAT under the Sun Solaris OS.

-- 


-------------------------------------------------------------------
Perry Lund                                 
Graduate Student CS             Instructor Applied Computer Science
UNI 1996 - 1997                                William Penn College
Cedar Falls, Iowa 50614                       Oskaloosa, Iowa 52577
-------------------------------------------------------------------

Re: SunOS Clear Screen

[Robert Dewar]

Perry asks

<<Where can I find information on accomplishing a clear screen command for
Ada.  I am running GNAT under the Sun Solaris OS.>>

The important thing to realize is that this is not an Ada question at all.
Ada gives you the capability of generating output streams of bytes. You
have to find out how to clear a screen given the particular terminal drivers
and environment you are using, and either you must write some special
sequence out (e.g. a Ctrl-L might work in some cases), or you need to call
a specialized routine (e.g. an appropriate routine in the curses library).

But don't look to Ada for a solution to this. Note that exactly the same
would be true in C, there is no way to clear a screen in C either!

Re: SunOS Clear Screen

[Larry Kilgallen]

In article <dewar.857058369@merv>, dewar@merv.cs.nyu.edu (Robert Dewar) writes:
> Perry asks
> 
> <<Where can I find information on accomplishing a clear screen command for
> Ada.  I am running GNAT under the Sun Solaris OS.>>
> 
> The important thing to realize is that this is not an Ada question at all.
> Ada gives you the capability of generating output streams of bytes. You
> have to find out how to clear a screen given the particular terminal drivers
> and environment you are using, and either you must write some special
> sequence out (e.g. a Ctrl-L might work in some cases), or you need to call
> a specialized routine (e.g. an appropriate routine in the curses library).

And for some "screens", where one is not emulating a dumb terminal,
there is no simple set of characters to write.

> But don't look to Ada for a solution to this. Note that exactly the same
> would be true in C, there is no way to clear a screen in C either!

I think the issue arises because of pathelogical intermixing of
languages and operating system environments in products like
Borland Pascal.  Folks who start in that realm don't see where
the Pascal ends and the Borland begins.

When one starts with a more academic approach to programming
languages, and advances to software engineering approaches,
the first response to the "how do I clear the screen" question
is "what screen" -- appropriate either to the rocket environment
with zero screens or the Airline Control Program with 4000 screens.

Larry Kilgallen

Re: SunOS Clear Screen

[Tom Moran]

> Borland Pascal.  Folks who start in that realm don't see where
> the Pascal ends and the Borland begins.
> 
> When one starts with a more academic approach to programming
> languages, and advances to software engineering approaches,
 A recent article (I forget where) showed a rather large (42% ?)
decrease over the last 5 years or so in CS BS degrees.  Does that mean
that the vast majority of current/future programmers are coming from the
'non-acedmenic' realm, and thus quite reasonably ask this kind of
question?

Re: SunOS Clear Screen

[Larry Kilgallen]

In article <3315FE64.2FC3@bix.com>, Tom Moran <tmoran@bix.com> writes:
>> Borland Pascal.  Folks who start in that realm don't see where
>> the Pascal ends and the Borland begins.
>> 
>> When one starts with a more academic approach to programming
>> languages, and advances to software engineering approaches,

>  A recent article (I forget where) showed a rather large (42% ?)
> decrease over the last 5 years or so in CS BS degrees.  Does that mean
> that the vast majority of current/future programmers are coming from the
> 'non-acedmenic' realm, and thus quite reasonably ask this kind of
> question?

I think that statistic will have less effect regarding new Ada
programmers than the availability of compilers which are inexpensive
ranging down to free.

Not only is an Ada compiler cheaper than Borland, but the organization
of the newsgroups is simpler :-).

Larry Kilgallen

Re: SunOS Clear Screen

[Jean-Etienne Doucet,149,6323]

In article 857058369@merv, dewar@merv.cs.nyu.edu (Robert Dewar) writes:
| Perry asks
| 
| <<Where can I find information on accomplishing a clear screen command for
| Ada.  I am running GNAT under the Sun Solaris OS.>>
| 
| The important thing to realize is that this is not an Ada question at all.
| 
| But don't look to Ada for a solution to this. Note that exactly the same
| would be true in C, there is no way to clear a screen in C either!
| 


All the Ada compilers I've worked with (including Gnat) on a Sparc with SunOS
clear the screen by simply calling Ada.Text_IO.New_Page.

Curiously, the usual <Escape> & "[2J" sequence doesn't seem to work...

Good luck.


_______________________________________________________________________________
Jean-Etienne Doucet / LAAS-CNRS / Toulouse, France       E-mail: doucet@laas.fr

Re: SunOS Clear Screen

[Keith Thompson]

In <5f65m9$re3@news.cict.fr> doucet@ripolin.laas.fr (Jean-Etienne Doucet,149,6323) writes:
[...]
> All the Ada compilers I've worked with (including Gnat) on a Sparc with SunOS
> clear the screen by simply calling Ada.Text_IO.New_Page.
> 
> Curiously, the usual <Escape> & "[2J" sequence doesn't seem to work...

That's odd.  Ada.Text_IO.New_Page typically prints a formfeed (control-L)
character.  That will clear the screen and home the cursor on a Sun
console (i.e., a Sun graphics monitor being used as a text terminal,
not running any window system), but not on most other modern terminals
or emulators.

What terminal or emulator are you using?

-- 
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