It may be helpful for you to post the pdlpp block code so that we can determine why it wouldn't be working. As far as I know there can be two problems with what you are doing.
in reply to Inline: where did the output go?
1) You are using Inline::Pdlpp incorrectly, so maybe your C code isn't even being evaluated (hence no printing).
2) The C code in the Pdlpp block is incorrect which is why nothing prints. This case does not make sense to me since you already tested that code independently from adding it to the block, which would mean you are quite sure of its correctness and of course is always a good practice, right?
Anyways, with a little more info and testing I think we may be able to correctly diagnose the illness ;)