1 files changed, 48 insertions, 0 deletions
diff --git a/stdio/fileno.c b/stdio/fileno.c
new file mode 100644
index 0000000000..da55300c8b
--- /dev/null
+++ b/stdio/fileno.c
@@ -0,0 +1,48 @@
+/* Copyright (C) 1991, 1993, 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <stdio.h>
+
+/* Return the system file descriptor associated with STREAM.  */
+int
+DEFUN(fileno, (stream), FILE *stream)
+{
+  extern void __stdio_check_funcs __P ((FILE *));
+
+  if (! __validfp (stream))
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  __stdio_check_funcs (stream);
+
+  if (stream->__io_funcs.__fileno == NULL)
+    {
+#ifdef EOPNOTSUPP
+      errno = EOPNOTSUPP;
+#else
+      errno = ENOSYS;
+#endif
+      return -1;
+    }
+
+  return (*stream->__io_funcs.__fileno) (stream->__cookie);
+}