If you do not plan to use any C++ stream I/0 operators or C++ stream type arguments in any given C++ file then you can use
#include <LppPure.hh>
instead if Lpp.hh.
This will result in slightly faster compiles and slightly smaller
binaries. LppPure.hh is the Pure Lisp include file and
Lpp.hh includes it. LppPure.hh does not include any
files, it is totally self contained. If in a given compilation unit
you are using no I/O or are only using Lisp style I/O such as
read, print, prin1, ... etc. then
LppPure.hh is sufficient. The Lpp library itself for example
uses LppPure.hh in most of its compilation units.
In this document whenever we talk about setting up optional
compilation parameters before including the Lpp.hh file this
also applies to wherever you are only including LppPure.hh.
If none of this matters to you, you can just use Lpp.hh all the
time, it is always perfectly safe.