[Guile-commits] 01/05: 'select' returns empty sets upon EINTR and EAGAIN.

[Ludovic Courtès]

civodul pushed a commit to branch stable-2.2
in repository guile.

commit f390afa0cc84eb84ed2cb3e03f542b991d4bb080
Author: Ludovic Courtès <address@hidden>
Date:   Fri Feb 16 14:05:04 2018 +0100

    'select' returns empty sets upon EINTR and EAGAIN.
    
    Fixes <https://bugs.gnu.org/30368>.
    
    * libguile/filesys.c (scm_select): Clear READ_SET, WRITE_SET, and
    EXCEPT_SET when RV < 0.
---
 libguile/filesys.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/libguile/filesys.c b/libguile/filesys.c
index e39dc4a..05dd2bd 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -1,5 +1,5 @@
 /* Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2006,
- *   2009, 2010, 2011, 2012, 2013, 2014, 2016, 2017 Free Software Foundation, 
Inc.
+ *   2009, 2010, 2011, 2012, 2013, 2014, 2016, 2017, 2018 Free Software 
Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -900,10 +900,20 @@ SCM_DEFINE (scm_select, "select", 3, 2, 0,
     int rv = scm_std_select (max_fd + 1,
                              &read_set, &write_set, &except_set,
                              time_ptr);
-    /* Let EINTR / EAGAIN cause a return to the user and let them loop
-       to run any asyncs that might be pending.  */
-    if (rv < 0 && errno != EINTR && errno != EAGAIN)
-      SCM_SYSERROR;
+    if (rv < 0)
+      {
+        /* Let EINTR / EAGAIN cause a return to the user and let them
+           loop to run any asyncs that might be pending.  */
+        if (errno != EINTR && errno != EAGAIN)
+          SCM_SYSERROR;
+        else
+          {
+            /* Return empty sets.  */
+            FD_ZERO (&read_set);
+            FD_ZERO (&write_set);
+            FD_ZERO (&except_set);
+          }
+      }
   }
 
   return scm_list_3 (retrieve_select_type (&read_set, read_ports_ready, reads),