Re: stdin/stdout in console applications

Edi Weitz wrote:
> Hi!
> 
> This message will show my complete ignorance about Windows issues and is 
> probaly only marginally related to Corman Lisp but, anyway, here it goes...
> 
> I want/need to write a little console application that acts like a Unix 
> "filter", i.e. it reads from stdin and writes to stdout. I wanted to 
> start small and wrote the simplest app I could imagine - something that 
> just lets everything go through. So, here's my only function:
> 
> (defun main ()
>    (loop for line = (read-line *standard-input* nil)
>          while line
>          do (format *standard-output* "~A~%" line)
>             (force-output *standard-output*))
>    (print 'done *standard-output*)
>    (force-output *standard-output*))
> 
> I created an EXE file with
> 
> (save-application "foo" 'main :console t :static t)
> 
> However, this raises lots of questions:
> 
> 1. If I start this from a console window it does what I expect, i.e. it 
> echos back the lines I type. But I don't know how to stop it - neither 
> Ctrl-D nor Ctrl-Z work. How do I send an EOF from the console?
> 
> 2. If I start it like "foo.exe < some_file.txt" I see nothing at all. 
> The program just hangs. What's happening?
> 
> 3. If I start it like "dir | foo.exe" I see the output from dir but the 
> programm crawls. It also hangs at the end of the directory listing and 
> doesn't stop nor does it show the DONE line. Again, what's happening? 
> And why is it so slow?
> 
> 4. Is this the right way to write such a program? I mean, can I expect 
> the program to end when my MAIN function is finished or do I have to 
> call some kind of EXIT function?
> 
> 5. I recall having read something about setting the mode (?) of stdin 
> and stdout to binary under Windows. Is that an issue here?
> 
> Sorry for (almost) half a dozen of dumb questions.
> 
> Thanks in advance,
> Edi.

Just tried this with Lispworks and

   (deliver 'main "foo" 0 :console t)

and at least 2. and 3. from above work fine there. The generated EXE 
also isn't slow when fed the output of dir.

Edi.


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get 128 Bit SSL Encryption!
http://us.click.yahoo.com/LIgTpC/vN2EAA/xGHJAA/SyjtlB/TM
---------------------------------------------------------------------~->

To unsubscribe from this group, send an email to:
[email protected]

 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/