From 997e521e2368c771822b9741e47850665f7715f1 Mon Sep 17 00:00:00 2001
From: Amirouche <amirouche@hypermove.net>
Date: Sun, 5 Mar 2017 21:37:09 +0100
Subject: [PATCH 2/2] make open-process public in (ice-9 popen)

---
 doc/ref/posix.texi     | 60 ++++++++++++++++++++++++++++++++++++++++++--------
 module/ice-9/popen.scm |  2 +-
 2 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/doc/ref/posix.texi b/doc/ref/posix.texi
index 4afe6bf..53f2230 100644
--- a/doc/ref/posix.texi
+++ b/doc/ref/posix.texi
@@ -2161,12 +2161,12 @@ expiry will be signalled.
 A real-time timer, counting down elapsed real time.  At zero it raises
 @code{SIGALRM}.  This is like @code{alarm} above, but with a higher
 resolution period.
-@end defvar 
+@end defvar
 
 @defvar ITIMER_VIRTUAL
 A virtual-time timer, counting down while the current process is
 actually using CPU.  At zero it raises @code{SIGVTALRM}.
-@end defvar 
+@end defvar
 
 @defvar ITIMER_PROF
 A profiling timer, counting down while the process is running (like
@@ -2175,7 +2175,7 @@ process's behalf.  At zero it raises a @code{SIGPROF}.
 
 This timer is intended for profiling where a program is spending its
 time (by looking where it is when the timer goes off).
-@end defvar 
+@end defvar
 
 @code{getitimer} returns the restart timer value and its current value,
 as a list containing two pairs.  Each pair is a time in seconds and
@@ -2260,6 +2260,48 @@ module@footnote{This module is only available on systems where the
 (use-modules (ice-9 popen))
 @end lisp
 
+@findex open-process
+@deffn {Scheme Procedure} open-process mode command [args...]
+
+Execute @code{command} in a subprocess passing @code{args} as arguments.
+
+@code{open-process} is the procedure used by and @code{open-pipe}
+and else to communicate with a subprocess using pipes. The notable
+difference with @code{open-pipe} API is that @code{open-process}
+does return multiple values.
+
+It returns @code{read-port}, @code{write-port} and @code{pid}. Depending
+on the @code{mode} you open the subprocess you can access
+@code{read-port} and @code{write-port} using regular port procedures.
+In particular you can close the @code{read-port} without closing the
+@code{write-port}. Don't forget to call @code{waitpid} on @code{pid}.
+
+Here is an example program that calls @code{tr} that request to replace
+@code{qsdf} with @code{asdf}:
+
+@lisp
+(use-modules (ice-9 rdelim))
+(use-modules (ice-9 popen))
+
+
+(define open-process (@@ (ice-9 popen) open-process))
+
+(define (qsdf->asdf string)
+  (call-with-values (lambda () (open-process OPEN_BOTH "tr" "qsdf" "asdf"))
+    (lambda (read-port write-port pid)
+      (display string write-port)
+      (close-port write-port)
+      (let ((str (read-string read-port)))
+        (close-port read-port)
+        (waitpid pid)
+        str))))
+
+
+(pk (qsdf->asdf "qsdf is fun!"))
+@result{} "asdf is fun!"
+@end lisp
+@end deffn
+
 @findex popen
 @deffn {Scheme Procedure} open-pipe command mode
 @deffnx {Scheme Procedure} open-pipe* mode prog [args...]
@@ -2356,11 +2398,11 @@ the garbage collector pick them up at some later time.
 @cindex network
 
 @menu
-* Network Address Conversion::  
-* Network Databases::           
-* Network Socket Address::      
-* Network Sockets and Communication::  
-* Internet Socket Examples::    
+* Network Address Conversion::
+* Network Databases::
+* Network Socket Address::
+* Network Sockets and Communication::
+* Internet Socket Examples::
 @end menu
 
 @node Network Address Conversion
@@ -3167,7 +3209,7 @@ effect but the value in Guile is always a pair.
 
 @c  Note that we refer only to ``man ip'' here.  On GNU/Linux it's
 @c  ``man 7 ip'' but on NetBSD it's ``man 4 ip''.
-@c 
+@c
 For IP level (@code{IPPROTO_IP}) the following @var{optname}s are
 defined (when provided by the system).  See @command{man ip} for what
 they mean.
diff --git a/module/ice-9/popen.scm b/module/ice-9/popen.scm
index 26a7e0a..37ea068 100644
--- a/module/ice-9/popen.scm
+++ b/module/ice-9/popen.scm
@@ -22,7 +22,7 @@
   :use-module (ice-9 threads)
   :use-module (srfi srfi-9)
   :export (port/pid-table open-pipe* open-pipe close-pipe open-input-pipe
-	   open-output-pipe open-input-output-pipe))
+	   open-output-pipe open-input-output-pipe open-process))
 
 (eval-when (expand load eval)
   (load-extension (string-append "libguile-" (effective-version))
-- 
2.9.3