New module 'isatty'.

* lib/unistd.in.h (isatty): New declaration.
* lib/isatty.c: New file, based on an idea of
Bastien Roucariès <roucaries.bastien@gmail.com>.
* m4/isatty.m4: New file.
* m4/unistd_h.m4 (gl_UNISTD_H): Test whether isatty is declared.
(gl_UNISTD_H_DEFAULTS): Initialize GNULIB_ISATTY, REPLACE_ISATTY.
* modules/unistd (Makefile.am): Substitute GNULIB_ISATTY,
REPLACE_ISATTY.
* modules/isatty: New file.
* doc/posix-functions/isatty.texi: Mention the new module.
Suggested by Paolo Bonzini.

1 files changed, 44 insertions, 0 deletions

diff --git a/lib/isatty.c b/lib/isatty.c
new file mode 100644
index 0000000000..ed8be82eff
--- /dev/null
+++ b/lib/isatty.c
@@ -0,0 +1,44 @@
+/* isatty() replacement.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+/* This replacement is enabled on native Windows.  */
+
+/* Get declarations of the Win32 API functions.  */
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+/* Get _get_osfhandle().  */
+#include "msvc-nothrow.h"
+
+#define IsConsoleHandle(h) (((long) (h) & 3) == 3)
+
+int
+isatty (int fd)
+{
+  /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR.  */
+  if (_isatty (fd))
+    {
+      HANDLE h = (HANDLE) _get_osfhandle (fd);
+      return IsConsoleHandle (h);
+    }
+  else
+    return 0;
+}