From fbb9921f8d29350fbc69e568f90cd66379502e9c Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Mon, 10 Mar 2014 00:23:15 -0700
Subject: * stream.c (pipe_close): Restructured the function a bit. Do not
 throw exceptions for normal process terminations, only for abnormal ones
 (terminated by a signal). Return the termination status instead of just t.

* txr.1: Fixed the neglected documentation of the optional boolean
argument of close-stream. Described the behaviors with regard
to pipes in more detail.
---
 ChangeLog | 11 +++++++++++
 stream.c  | 43 ++++++++++++++++++++++---------------------
 txr.1     | 19 ++++++++++++++++++-
 3 files changed, 51 insertions(+), 22 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ca9ae1ff..55fec2ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2014-03-10  Kaz Kylheku  <kaz@kylheku.com>
+
+	* stream.c (pipe_close): Restructured the function a bit.
+	Do not throw exceptions for normal process terminations, only for
+	abnormal ones (terminated by a signal). Return the termination
+	status instead of just t.
+
+	* txr.1: Fixed the neglected documentation of the optional boolean
+	argument of close-stream. Described the behaviors with regard
+	to pipes in more detail.
+
 2014-03-09  Kaz Kylheku  <kaz@kylheku.com>
 
 	* match.c (v_trailer): Fix segfault. The code which
diff --git a/stream.c b/stream.c
index 912e6a80..7d073fc1 100644
--- a/stream.c
+++ b/stream.c
@@ -654,36 +654,37 @@ static val pipe_close(val stream, val throw_on_error)
 #endif
     h->f = 0;
 
-    if (status != 0 && throw_on_error) {
-      if (status < 0) {
+    if (status < 0) {
+      if (throw_on_error)
         uw_throwf(process_error_s,
                   lit("unable to obtain status of command ~a: ~a/~s"),
                   stream, num(errno), string_utf8(strerror(errno)), nao);
+    } else {
 #ifdef HAVE_SYS_WAIT
+      if (throw_on_error) {
+        if (WIFSIGNALED(status)) {
+          int termsig = WTERMSIG(status);
+          uw_throwf(process_error_s, lit("pipe ~a terminated by signal ~a"),
+                    stream, num(termsig), nao);
 #ifndef WIFCONTINUED
 #define WIFCONTINUED(X) 0
 #endif
-      } else if (WIFEXITED(status)) {
+        } else if (WIFSTOPPED(status) || WIFCONTINUED(status)) {
+          uw_throwf(process_error_s,
+                    lit("processes of closed pipe ~a still running"),
+                    stream, nao);
+        }
+      }
+      if (WIFEXITED(status)) {
         int exitstatus = WEXITSTATUS(status);
-        uw_throwf(process_error_s, lit("pipe ~a terminated with status ~a"),
-                  stream, num(exitstatus), nao);
-      } else if (WIFSIGNALED(status)) {
-        int termsig = WTERMSIG(status);
-        uw_throwf(process_error_s, lit("pipe ~a terminated by signal ~a"),
-                  stream, num(termsig), nao);
-
-      } else if (WIFSTOPPED(status) || WIFCONTINUED(status)) {
-        uw_throwf(process_error_s,
-                  lit("processes of closed pipe ~a still running"),
-                  stream, nao);
-      } else {
-        uw_throwf(file_error_s, lit("strange status in when closing pipe ~a"),
-                  stream, nao);
-#endif
+        return num(exitstatus);
       }
-    }
-
-    return status == 0 ? t : nil;
+#else
+      if (status != 0 && throw_on_error)
+        uw_throwf(process_error_s, lit("closing pipe ~a failed"), stream, nao);
+#endif
+      return status == 0 ? zero : nil;
+    } 
   }
   return nil;
 }
diff --git a/txr.1 b/txr.1
index f48f1360..87e0b624 100644
--- a/txr.1
+++ b/txr.1
@@ -11685,7 +11685,7 @@ finalized, so that further output is no longer possible.
 .TP
 Syntax:
 
-  (close-stream <stream>)
+  (close-stream <stream> [<throw-on-error-p>])
 
 .TP
 Description:
@@ -11697,6 +11697,23 @@ to operating system files or devices, will perform a close of the underlying
 file descriptor, and dissociate that descriptor from the stream. Any buffered
 data is flushed first.
 
+The function returns a boolean true value if the close has occurred without
+errors, otherwise nil.
+
+For most streams, "without errors" means that any buffered output data is
+flushed successfully.
+
+For command and process pipes (see open-command and open-process), success also
+means that the process terminates normally, with a successful error code, or an
+unsuccessul one. An abnormal termination is considered an error, as
+as is the inability to retrieve the termination status, as well as the situation
+that the process continues running in spite of the close attempt.
+Detecting these situations is platform specific.
+
+If the <throw-on-error-p> argument is specified, and isn't nil, then the
+function throws an exception if an error occurs during the close operation
+instead of returning nil.
+
 .SS Functions get-line, get-char and get-byte
 
 .TP
-- 
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