X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frrdgraph_rpn.src;h=f9ac7fedb9959cb66390026df5dd1fe921009c20;hb=e6271afb13033053281a06abda00e06bd007fba6;hp=8b5d49bbf92a842af2e74501717cca1d1ef5c4e1;hpb=09a9d41221b120a4caa547da7d431a6e5a51a885;p=rrdtool.git

diff --git a/doc/rrdgraph_rpn.src b/doc/rrdgraph_rpn.src
index 8b5d49b..f9ac7fe 100644
--- a/doc/rrdgraph_rpn.src
+++ b/doc/rrdgraph_rpn.src
@@ -123,6 +123,20 @@ set or otherwise the result of this B<CDEF> at the previous time
 step. This allows you to do calculations across the data.  This
 function cannot be used in B<VDEF> instructions.
 
+B<PREV(vname)>
+
+Pushes an I<unknown> value if this is the first value of a data
+set or otherwise the result of vname variable at the previous time
+step. This allows you to do calculations across the data.  This
+function cannot be used in B<VDEF> instructions.
+
+B<COUNT>
+
+Pushes the number 1 if this is the first value of the data set, the 
+number 2 if it is the second, and so on. This special value, allows 
+you to make calculations based on the position of the value within 
+the data set. This function cannot be used in B<VDEF> instructions.
+
 Z<>
 
 =item Time