Index: /trunk/archive/pslib/include/psMath.h
===================================================================
--- /trunk/archive/pslib/include/psMath.h	(revision 206)
+++ /trunk/archive/pslib/include/psMath.h	(revision 207)
@@ -1,2 +1,4 @@
+#if !defined (PS_MATH_H)
+#define PS_MATH_H
 
 typedef enum {				// type of val is:
@@ -37,4 +39,5 @@
 /*** example 1: data type abstraction */
 
+/*
 psImage A, Y;
 psDI a, b, x, y;
@@ -48,11 +51,14 @@
 y = psDataItemUnaryOp (NULL, b, "log");
 Y = y.v;
+*/
 
 /*** example 2: explicit functions ***/
 
+/*
 psImage A, B, Y;
 
 B = psImageOpScalar (NULL, A, "^", 2.0);
 Y = psImageOp (NULL, B, "log");
+*/
 
 /* in the later example, we would have the following functions */
@@ -86,8 +92,10 @@
 /*** example 3: embedded data type */
 
+/*
 psImage A, B, Y;
 
 B = psBinaryOp (NULL, A, "^", psScalar(2));
 Y = psUnaryOp (NULL, B, "log");
+*/
 
 /** in this method, the data types (psImage, psVector) include embedded information about their data type in
@@ -111,2 +119,4 @@
     psDimension dim;
 } psTypeInfo;
+
+#endif