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[Patch] Add Comment to io/fcntl.h
- From: Patsy Franklin <pfrankli at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Mon, 25 Feb 2013 09:53:28 -0500
- Subject: [Patch] Add Comment to io/fcntl.h
- Reply-to: pfrankli at redhat dot com
This patch adds a comment explaining why it's OK for
AT_REMOVEDIR and AT_EACCESS to have the same defined value.
It should be noted that AT_EACCESS is not yet reserved in
the Linux kernel and it should to avoid future confusion.
OK to checkin?
index 61834ce..9c149cb 100644
--- a/io/fcntl.h
+++ b/io/fcntl.h
@@ -129,6 +129,12 @@ typedef __pid_t pid_t;
# define SEEK_END 2 /* Seek from end of file. */
#endif /* XPG */
+/* AT_REMOVEDIR AND AT_EACCESS have the same defined value below.
+ * The AT_EACCESS value is only used by faccessat () and the AT_REMOVEDIR
+ * value is only used by unlinkat (). The two functions do completely different
+ * things and therefore the flags can be allowed to overlap.
+ * For example, passing AT_REMOVEDIR to faccessat() would be undefined behavior
+ * and thus treating it equivalent to AT_EACCESS is valid undefined behavior.*/
#ifdef __USE_ATFILE
# define AT_FDCWD -100 /* Special value used to indicate
the *at functions should use the