The BOOST_PP_CAT macro concatenates its arguments after they have been expanded.

Usage

BOOST_PP_CAT(a, b)

Arguments

a
The left operand of the concatenation.
b
The right operand of the concatenation.

Remarks

The preprocessor token-pasting operator (##) prevents arguments from expanding.  This macro allows its arguments to expand before concatenation.
Concatenation must not result in an invocation of a macro that uses BOOST_PP_CAT.  If that happens, BOOST_PP_CAT will not expand the second time.

Requirements

Header:  <boost/preprocessor/cat.hpp>

Sample Code

#include <boost/preprocessor/cat.hpp>

BOOST_PP_CAT(x, BOOST_PP_CAT(y, z)) // expands to xyz