X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frrdgraph_data.pod;h=95b1ec70bb45a6f379ac500fa0df2519f866a890;hb=99bc538e0bef411b7d757f79a527629b99c40870;hp=dba53f3720a4a302b2cc8651545eed3a993bbd89;hpb=9b8a8e557d4c271ad4efe95c4b7bb7f0803e729c;p=rrdtool.git

diff --git a/doc/rrdgraph_data.pod b/doc/rrdgraph_data.pod
index dba53f3..95b1ec7 100644
--- a/doc/rrdgraph_data.pod
+++ b/doc/rrdgraph_data.pod
@@ -20,7 +20,11 @@ instructions use a language called B<RPN> which is described in its
 own manual page.
 
 Variable names (I<vname>) must be made up strings of the following characters
-C<A-Z, a-z, 0-9, -,_>, starting with a letter and a maximum length of 255 characters.
+C<A-Z, a-z, 0-9, -,_> and a maximum length of 255 characters.
+
+When picking variable names, make sure you do not choose a name that is
+already taken by an RPN operator. A safe bet it to use lowercase or
+mixedcase names for variables since operators will always be in uppercase.
 
 =head1 DEF
 
@@ -71,6 +75,9 @@ elements.
 
 Example: C<VDEF:avg=mydata,AVERAGE>
 
+Note that currently only aggregation functions work in VDEF rpn expressions.
+Patches to change this are welcome.
+
 =head1 CDEF
 
 B<CDEF>:I<vname>=I<RPN expression>
@@ -94,6 +101,7 @@ Make sure to read L<rrdgraph_examples> for tipsE<amp>tricks.
 
 =head1 AUTHOR
 
-Program by Tobias Oetiker E<lt>oetiker@ee.ethz.chE<gt>
+Program by Tobias Oetiker E<lt>tobi@oetiker.chE<gt>
 
-This manual page by Alex van den Bogaerdt E<lt>alex@ergens.op.het.netE<gt>
+This manual page by Alex van den Bogaerdt E<lt>alex@vandenbogaerdt.nlE<gt>
+with corrections and/or additions by several people