Chasm generates Fortran-C++ interfacing code.
flibcpp uses SWIG-Fortran to expose useful functionality from the C++ standard library to Fortran 2003 application developers.
FortWrap generates code to call Fortran from C++.
f2cpp converts Fortran 77 code to C++, by Victor Liu
ObjexxFCL is a C++ library that supports integration of C++ and Fortran, providing Fortran-compatible array and string support.
Shroud generates Fortran and Python wrappers for C and C++ libraries.