On Jan 11 2012, Tobias Burnus wrote:
I assume that it is sufficient for you to change the name in the C++ file. However, I want to point out that Fortran also provides means for better interoperability with C ["bind(C)"] - and thus with C++'s 'extern "C"', cf. http://gcc.gnu.org/onlinedocs/gfortran/Mixed_002dLanguage-Programming.html
A slight correction, which is more for us geeks than the OP :-) Fortran does not formally support interoperability with C++ via that route, and it isn't absolutely clear what C++ means by C linkage. Both Fortran and C++ need to use a lot of created external names, and have (moderately) advanced memory management and some error handling; it isn't unlikely that those will conflict. It is also unclear exactly which Fortran interoperability features will map to C enough to interoperate with the ways that C++ maps its equivalent to C. I raised this at WG5 and got the answer that I expected (i.e. that Fortran does not formally support interoperability with C++). The latter is easier - 7.5 [dcl.link] p.3 says "Every implementation shall provide for linkage to functions written in the C programming language". So far, so good. But there are some potential semantic discrepancies that are swept under the carpet by the C++ standard, such as IEEE 754 'support'. Anyone who relies on those and uses Fortran/C++ interoperability had better prepare to be surprised! I don't know of a clear and complete specification of how much of this the GCC suite supports, but should be happy to cooperate with any attempt to write one. If there IS one, I apologise, and should appreciate a reference!
Additionally, I want to point out that without using Bind(C) there might be additional issues - and differences between compilers; in particular, the way, "float"/"REAL" values and complex-number-returning functions are implemented, differs among compilers.
Yes. Very much so. In particular, complex-number-returning functions are a minefield even with BIND(C) or between C++ and C and are hopeless without it or 'extern "C"' :-( Regards, Nick Maclaren.
