[glibc] manual: clarify fopen with the x flag

[glibc] manual: clarify fopen with the x flag

[Paul Eggert]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ef4e158c736d067304164c3daa763e4f425af248

commit ef4e158c736d067304164c3daa763e4f425af248
Author: Paul Eggert <eggert@cs.ucla.edu>
Date:   Wed Dec 11 09:34:06 2019 -0800

    manual: clarify fopen with the x flag
    
    * manual/stdio.texi (Opening Streams): Say how glibc's
    implementation of fopen with "x" follows ISO C11.

Diff:
---
 manual/stdio.texi | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/manual/stdio.texi b/manual/stdio.texi
index bbd3061..8051603 100644
--- a/manual/stdio.texi
+++ b/manual/stdio.texi
@@ -216,7 +216,9 @@ exists, @code{fopen} fails rather than opening it.  If you use
 file.  This is equivalent to the @code{O_EXCL} option to the
 @code{open} function (@pxref{Opening and Closing Files}).
 
-The @samp{x} modifier is part of @w{ISO C11}.
+The @samp{x} modifier is part of @w{ISO C11}, which says the file is
+created with exclusive access; in @theglibc{} this means the
+equivalent of @code{O_EXCL}.
 @end table
 
 The character @samp{b} in @var{opentype} has a standard meaning; it