vasnprintf: Add more tests.

[gnulib.git] / doc / posix-functions / stdin.texi

diff --git a/doc/posix-functions/stdin.texi b/doc/posix-functions/stdin.texi
index dfa13ec..0283542 100644 (file)
--- a/doc/posix-functions/stdin.texi
+++ b/doc/posix-functions/stdin.texi
@@ -17,4 +17,11 @@ stdin is created in 32-bit mode instead of 64-bit mode: Cygwin 1.5.x.
 One workaround is to use freopen(NULL, ``r'', stdin) on Cygwin 1.5.21
 or newer.  Another is to use the gnulib ftello module and do
 ftello(stdin).
+@item
+POSIX states that a setuid application can guarantee that fd 0 is
+open, but some systems guarantee this even for non-setuid programs.
+If an application is executed with fd 0 closed, use of @code{stdin}
+can affect an unrelated file that happened to be assigned to fd 0.
+The gnulib *-safer modules may be used to guarantee that fd 0 stays
+reserved for @code{stdin}.
 @end itemize