- if (errnum > 0 && errnum <= sys_nerr)
- return _(sys_errlist[errnum]);
- return _("Unknown system error");
+# if GNULIB_FREOPEN_SAFER
+ /* Use of gnulib's freopen-safer module normally ensures that
+ fileno (stdout) == 1
+ whenever stdout is open. */
+ stdout_fd = STDOUT_FILENO;
+# else
+ /* POSIX states that fileno (stdout) after fclose is unspecified. But in
+ practice it is not a problem, because stdout is statically allocated and
+ the fd of a FILE stream is stored as a field in its allocated memory. */
+ stdout_fd = fileno (stdout);
+# endif
+ /* POSIX states that fflush (stdout) after fclose is unspecified; it
+ is safe in glibc, but not on all other platforms. fflush (NULL)
+ is always defined, but too draconian. */
+ if (0 <= stdout_fd && is_open (stdout_fd))
+#endif
+ fflush (stdout);