So you don't know how I could directly port this to Swift--or make an indirect port?
On 1/13/17, Jens Alfke <j...@mooseyard.com> wrote: > >> On Jan 13, 2017, at 8:18 AM, Ethin Probst via swift-users >> <swift-users@swift.org> wrote: >> >> I was wondering how I could go about using the Boost library project >> (among others) in swift? > > No, it’s generally not feasible to use C++ libraries from any other > language. The main reasons are that (a) name-mangling of C++ functions means > that there’s no reliable way to tell the other language the name of the > function you want to call, and (b) C++ has so many language features that > are tightly entwined with the way you call functions — constructors, > copying, assignment, references, implicit conversions, operator overloading, > etc. > > In the simple example you gave there are several warning signs: > * BOOST_LOG_TRIVIAL etc. appear to be macros since they’re in all caps. Who > knows what functions they actually call? > * The “<<“ operator expands [unmangles] to some complex function name which > is very compiler-dependent. > * It’s very probable that the “<<“ operator is defined as an inline > function, so it may not even appear in the binary of the compiled Boost > library at all. > * The C string constants on the right hand side are probably being > implicitly converted to C++ std::strings before the call. Or maybe not. And > the conversion likely happens on the caller’s side, i.e. the compiler has to > know to create a std::string before calling and then destruct it > afterwards. > > The only practical way to call a C++ API from another language is to write > glue code, a set of functions that call the library, but which have a plain > C API and use only C types. Pretty much any language has a way to call C > functions, so you can now call the C API which will call the C++ code. > > —Jens -- Signed, Ethin D. Probst _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
