Possibly fix bug #13086 with losing track of subprocesses on MS-Windows.

 src/w32proc.c (new_child, delete_child, find_child_pid): For a
 subprocess, consider its slot being in use as long as its process
 handle (procinfo.hProcess) is not NULL.  This avoids reusing the
 slot when a new process is started immediately after killing
 another one, without waiting enough time for the first process to
 be reaped and resources allocated for it be orderly freed.
 Suggested by Fabrice Popineau <fabrice.popineau@supelec.fr>.

2 files changed, 17 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 645da892971..6e7f771d220 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,14 @@
+2012-12-21  Eli Zaretskii  <eliz@gnu.org>
+
+        * w32proc.c (new_child, delete_child, find_child_pid): For a
+        subprocess, consider its slot being in use as long as its process
+        handle (procinfo.hProcess) is not NULL.  This avoids reusing the
+        slot when a new process is started immediately after killing
+        another one, without waiting enough time for the first process to
+        be reaped and resources allocated for it be orderly freed.
+        (Bug#13086)
+        Suggested by Fabrice Popineau <fabrice.popineau@supelec.fr>.
+
 2012-12-21  Chong Yidong  <cyd@gnu.org>
 
         * buffer.c (Fset_buffer_major_mode): Doc fix (Bug#13231).
diff --git a/src/w32proc.c b/src/w32proc.c
index e3c54fe5460..03360075a09 100644
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -795,7 +795,7 @@ new_child (void)
   DWORD id;
 
   for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
-    if (!CHILD_ACTIVE (cp))
+    if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess == NULL)
       goto Initialize;
   if (child_proc_count == MAX_CHILDREN)
     return NULL;
@@ -852,7 +852,7 @@ delete_child (child_process *cp)
     if (fd_info[i].cp == cp)
       emacs_abort ();
 
-  if (!CHILD_ACTIVE (cp))
+  if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess == NULL)
     return;
 
   /* reap thread if necessary */
@@ -896,7 +896,8 @@ delete_child (child_process *cp)
   if (cp == child_procs + child_proc_count - 1)
     {
       for (i = child_proc_count-1; i >= 0; i--)
-        if (CHILD_ACTIVE (&child_procs[i]))
+        if (CHILD_ACTIVE (&child_procs[i])
+            || child_procs[i].procinfo.hProcess != NULL)
           {
             child_proc_count = i + 1;
             break;
@@ -913,7 +914,8 @@ find_child_pid (DWORD pid)
   child_process *cp;
 
   for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
-    if (CHILD_ACTIVE (cp) && pid == cp->pid)
+    if ((CHILD_ACTIVE (cp) || cp->procinfo.hProcess != NULL)
+        && pid == cp->pid)
       return cp;
   return NULL;
 }