1 files changed, 62 insertions, 0 deletions
diff --git a/private/crt32/lowio/isatty.c b/private/crt32/lowio/isatty.c
new file mode 100644
index 000000000..9bb931d18
--- /dev/null
+++ b/private/crt32/lowio/isatty.c
@@ -0,0 +1,62 @@
+/***
+*isatty.c - check if file handle refers to a device
+*
+*	Copyright (c) 1989-1992, Microsoft Corporation. All rights reserved.
+*
+*Purpose:
+*	defines _isatty() - check if file handle refers to a device
+*
+*Revision History:
+*	06-08-89  PHG	Module created
+*	03-12-90  GJF	Made calling type _CALLTYPE1, added #include
+*			<cruntime.h> and fixed the copyright. Also, cleaned
+*			up the formatting a bit.
+*	08-14-90  SBM	Compiles cleanly with -W3, minor optimization
+*	09-28-90  GJF	New-style function declarator.
+*	12-04-90  GJF	Appended Win32 version onto the source with #ifdef-s.
+*			It's not worth it to try to merge the versions more
+*			closely.
+*	12-06-90  SRW	Changed to use _osfile and _osfhnd instead of _osfinfo
+*	01-16-91  GJF	ANSI naming.
+*	02-13-92  GJF	Replaced _nfile by _nhandle for Win32.
+*
+*******************************************************************************/
+
+#include <cruntime.h>
+#include <msdos.h>
+#include <internal.h>
+#include <io.h>
+
+/***
+*int _isatty(handle) - check if handle is a device
+*
+*Purpose:
+*	Checks if the given handle is associated with a character device
+*	(terminal, console, printer, serial port)
+*
+*Entry:
+*	int handle - handle of file to be tested
+*
+*Exit:
+*	returns non-0 if handle refers to character device,
+*	returns 0 otherwise
+*
+*Exceptions:
+*
+*******************************************************************************/
+
+int _CALLTYPE1 _isatty (
+	int fh
+	)
+{
+	/* see if file handle is valid, otherwise return FALSE */
+#ifdef	_WIN32_
+	if ( (unsigned)fh >= (unsigned)_nhandle )
+#else
+	if ((unsigned)fh >= (unsigned)_nfile)
+#endif
+		return 0;
+
+	/* check file handle database to see if device bit set */
+	return (int)(_osfile[fh] & FDEV);
+}