diff --git a/src/structs.h b/src/structs.h
index 9c0e046..af0a6fd 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1133,25 +1133,43 @@
 #  ifdef PROTO
 typedef long		    varnumber_T;
 typedef unsigned long	    uvarnumber_T;
+#define VARNUM_MIN	    LONG_MIN
+#define VARNUM_MAX	    LONG_MAX
+#define UVARNUM_MAX	    ULONG_MAX
 #  else
 typedef __int64		    varnumber_T;
 typedef unsigned __int64    uvarnumber_T;
+#define VARNUM_MIN	    _I64_MIN
+#define VARNUM_MAX	    _I64_MAX
+#define UVARNUM_MAX	    _UI64_MAX
 #  endif
 # elif defined(HAVE_STDINT_H)
 typedef int64_t		    varnumber_T;
 typedef uint64_t	    uvarnumber_T;
+#define VARNUM_MIN	    INT64_MIN
+#define VARNUM_MAX	    INT64_MAX
+#define UVARNUM_MAX	    UINT64_MAX
 # else
 typedef long		    varnumber_T;
 typedef unsigned long	    uvarnumber_T;
+#define VARNUM_MIN	    LONG_MIN
+#define VARNUM_MAX	    LONG_MAX
+#define UVARNUM_MAX	    ULONG_MAX
 # endif
 #else
 /* Use 32-bit Number. */
 # if VIM_SIZEOF_INT <= 3	/* use long if int is smaller than 32 bits */
 typedef long		    varnumber_T;
 typedef unsigned long	    uvarnumber_T;
+#define VARNUM_MIN	    LONG_MIN
+#define VARNUM_MAX	    LONG_MAX
+#define UVARNUM_MAX	    ULONG_MAX
 # else
 typedef int		    varnumber_T;
 typedef unsigned int	    uvarnumber_T;
+#define VARNUM_MIN	    INT_MIN
+#define VARNUM_MAX	    INT_MAX
+#define UVARNUM_MAX	    UINT_MAX
 # endif
 #endif