X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frrdgraph_data.pod;h=fc0c2fc360669ed788e20042f7ad92ae9ace4c45;hb=2522d72d7da75ab2b058578e60df95319790b9b5;hp=64c559aba27f36485883ea513484487a46cdc112;hpb=342b22c3e74a10d7049285c2cea7383676bcfc95;p=rrdtool.git

diff --git a/doc/rrdgraph_data.pod b/doc/rrdgraph_data.pod
index 64c559a..fc0c2fc 100644
--- a/doc/rrdgraph_data.pod
+++ b/doc/rrdgraph_data.pod
@@ -22,6 +22,10 @@ own manual page.
 Variable names (I<vname>) must be made up strings of the following 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
 
 B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>]
@@ -71,7 +75,7 @@ elements.
 
 Example: C<VDEF:avg=mydata,AVERAGE>
 
-Note that currently only agregation functions work in VDEF rpn expressions.
+Note that currently only aggregation functions work in VDEF rpn expressions.
 Patches to change this are welcome.
 
 =head1 CDEF