Improve handling of subprocess shutdown on MS-Windows.

 src/w32proc.c (reader_thread): Do not index fd_info[] with negative
 values.
 (reader_thread): Exit when cp->status becomes STATUS_READ_ERROR
 after WaitForSingleObject returns normally.  This expedites reader
 thread shutdown when delete_child triggers it.
 (reap_subprocess): More accurate commentary for why we call
 delete_child only when cp->fd is negative.
 src/w32.c (sys_close): Do not call delete_child on a subprocess
 whose handle is not yet closed.  Instead, set its file descriptor
 to a negative value, so that reap_subprocess will call
 delete_child on that subprocess when its SIGCHLD arrives.  This
 avoids closing handles used for communications between sys_select
 and reader_thread, which doesn't give sys_select a chance to
 notice that the process exited and invoke the SIGCHLD handler for
 it.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2723d8f92ec..c7502104ddf 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,22 @@
+2012-12-23  Eli Zaretskii  <eliz@gnu.org>
+
+        * w32proc.c (reader_thread): Do not index fd_info[] with negative
+        values.
+        (reader_thread): Exit when cp->status becomes STATUS_READ_ERROR
+        after WaitForSingleObject returns normally.  This expedites reader
+        thread shutdown when delete_child triggers it.
+        (reap_subprocess): More accurate commentary for why we call
+        delete_child only when cp->fd is negative.
+
+        * w32.c (sys_close): Do not call delete_child on a subprocess
+        whose handle is not yet closed.  Instead, set its file descriptor
+        to a negative value, so that reap_subprocess will call
+        delete_child on that subprocess when its SIGCHLD arrives.  This
+        avoids closing handles used for communications between sys_select
+        and reader_thread, which doesn't give sys_select a chance to
+        notice that the process exited and invoke the SIGCHLD handler for
+        it.
+
 2012-12-23  Jan Djärv  <jan.h.d@swipnet.se>
 
         * nsfns.m (Fns_do_applescript): Run event loop until script has