1 files changed, 36 insertions, 0 deletions

diff --git a/gl/cloexec.h b/gl/cloexec.h
index c25921d6..e3a2cb85 100644
--- a/gl/cloexec.h
+++ b/gl/cloexec.h
@@ -1,2 +1,38 @@
+/* closexec.c - set or clear the close-on-exec descriptor flag
+
+   Copyright (C) 2004, 2009-2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
 #include <stdbool.h>
+
+/* Set the `FD_CLOEXEC' flag of DESC if VALUE is true,
+   or clear the flag if VALUE is false.
+   Return 0 on success, or -1 on error with `errno' set.
+
+   Note that on MingW, this function does NOT protect DESC from being
+   inherited into spawned children.  Instead, either use dup_cloexec
+   followed by closing the original DESC, or use interfaces such as
+   open or pipe2 that accept flags like O_CLOEXEC to create DESC
+   non-inheritable in the first place.  */
+
 int set_cloexec_flag (int desc, bool value);
+
+/* Duplicates a file handle FD, while marking the copy to be closed
+   prior to exec or spawn.  Returns -1 and sets errno if FD could not
+   be duplicated.  */
+
+int dup_cloexec (int fd);