1 files changed, 83 insertions, 0 deletions
diff --git a/lib/isatty.c b/lib/isatty.c
new file mode 100644
index 0000000..d8071fb
--- /dev/null
+++ b/lib/isatty.c
@@ -0,0 +1,83 @@
+/* isatty() replacement.
+   Copyright (C) 2012-2016 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.  */
+
+#include <errno.h>
+
+/* Get declarations of the Win32 API functions.  */
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+#include "msvc-inval.h"
+
+/* Get _get_osfhandle().  */
+#include "msvc-nothrow.h"
+
+static BOOL IsConsoleHandle (HANDLE h)
+{
+  DWORD mode;
+  return GetConsoleMode (h, &mode) != 0;
+}
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+static int
+_isatty_nothrow (int fd)
+{
+  int result;
+
+  TRY_MSVC_INVAL
+    {
+      result = _isatty (fd);
+    }
+  CATCH_MSVC_INVAL
+    {
+      result = 0;
+    }
+  DONE_MSVC_INVAL;
+
+  return result;
+}
+#else
+# define _isatty_nothrow _isatty
+#endif
+
+/* Determine whether FD refers to a console device.  Return 1 if yes.
+   Return 0 and set errno if no. (ptsname_r relies on the errno value.)  */
+int
+isatty (int fd)
+{
+  HANDLE h = (HANDLE) _get_osfhandle (fd);
+  if (h == INVALID_HANDLE_VALUE)
+    {
+      errno = EBADF;
+      return 0;
+    }
+  /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR.
+     But it does not set errno when it returns 0.  */
+  if (_isatty_nothrow (fd))
+    {
+      if (IsConsoleHandle (h))
+        return 1;
+    }
+  errno = ENOTTY;
+  return 0;
+}