--- mstools/posix/h/unistd.h	2018/08/09 18:22:18	1.1
+++ mstools/posix/h/unistd.h	2018/08/09 18:24:37	1.1.1.2
@@ -11,12 +11,6 @@ Abstract:
    This module contains the "symbolic constants and structures referenced
    elsewhere in the standard" IEEE P1003.1/Draft 13.
 
-Author:
-
-   Mark Lucovsky     21-Feb-1989
-
-Revision History:
-
 --*/
 
 #ifndef _UNISTD_
@@ -24,6 +18,10 @@ Revision History:
 
 #include <sys/types.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define STDIN_FILENO	0
 #define STDOUT_FILENO	1
 #define STDERR_FILENO	2
@@ -59,7 +57,7 @@ Revision History:
 
 #define  _POSIX_CHOWN_RESTRICTED 1
 #define  _POSIX_NO_TRUNC	 1
-#define  _POSIX_VDISABLE	(-1)
+#define  _POSIX_VDISABLE	 0
 
 /*
  * Section 4.8.1
@@ -73,7 +71,9 @@ Revision History:
 #define _SC_OPEN_MAX		5
 #define _SC_JOB_CONTROL		6
 #define _SC_SAVED_IDS		7
-#define _SC_VERSION		8
+#define _SC_STREAM_MAX		8
+#define _SC_TZNAME_MAX		9
+#define _SC_VERSION		10
 
 /*
  * Section 5.7.1
@@ -90,6 +90,10 @@ Revision History:
 #define _PC_NO_TRUNC		8
 #define _PC_VDISABLE		9
 
+#ifndef NULL
+#define NULL	((void *)0)
+#endif 
+
 /*
  * Function Prototypes
  */
@@ -157,4 +161,8 @@ off_t _CRTAPI1 lseek(int, off_t, int);
 
 char * _CRTAPI1 cuserid(char *);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _UNISTD_ */