[Ecls-list] new user

[Juan Jose Garcia Ripoll]

On Sun, 2006-05-21 at 15:18 +0200, Lelanthran Manickum wrote:
> I am trying to use (pipe-open "/bin/bash") but I'm
> not getting the results I expect. I expected it
> to work like the clisp (make-pipe-io-stream) function.

Sorry for the delay in answering. ECL's pipe-open is an old function
which is being deprecated. It has the problem that it opens a pipe in
only one direction: either you write to the program's input or you read
the program's output. This is a limitation of using popen().

Not so long ago we ported a function which is compatible to CMUCL's
run-program. The function signature is
	(ext::run-program (command argv &key (input @':stream')
			 (output @':stream') (error @'t'))
As you see, you pass the name of the program, a list of arguments (each
argument being a string), and also select which streams you want to be
able to read from or write to.

An example which uses ImageMagik to read information from a JPG file:


(defun compute-image-height (filename)
  (let ((pipe (si::run-program "identify"
			       `("-format" "%h" ,(namestring (truename filename)))
			       :input nil
			       :error nil)))
    (prog1 (read pipe)
      (read-line)
      (close pipe))))


Regards,

Juanjo
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