Bison and C++

[Hans Aberg]

It is fact possible to have the top-node in C even though the rest is
written in C++:

One simply writes in C++:
    extern "C" { int main(...) { /* C++ code */ } }
or
    extern "C" int main(...) { /* C++ code */ }
as the "extern" clause only applies to the type of _linkage_, and not what
is in the definition of it. Instead of "C", one could also have "Pascal",
"Fortran" or whatever, only if the compiler can handle it; but one is
guaranteed that "C" will always work.

Therefore the use of C++ is only restricted to the availability of
compilers. My guess is that as the C++ standard ANSI/ISO/IEC 14882-1998 is
now a few years old and available from ANSI for only $18 (same price as for
the new C standard ANSI/ISO/IEC 9899-1999 formerly called C9X),
availability is rife.

One reasonable approach for a program that might be used as a library from
a program written in C is to supply a C entry-point.

  Hans Aberg