A Slice identifier maps to an identical C++ identifier. For example, the Slice identifier Clock becomes the C++ identifier Clock. There is one exception to this rule: if a Slice identifier is the same as a C++ keyword, the corresponding C++ identifier is prefixed with _cpp_. For example, the Slice identifier while is mapped as _cpp_while.
A single Slice identifier often results in several C++ identifiers. For example, for a Slice interface named Foo, the generated C++ code uses the identifiers Foo and FooPrx (among others). If the interface has the name while, the generated identifiers are _cpp_while and whilePrx (not _cpp_whilePrx), that is, the prefix is applied only to those generated identifiers that actually require it.
You should try to avoid such identifiers as much as possible.