How do I use C + + in Go?

This is a creation in Article, where the information may have evolved or changed.

Update: I ' ve succeeded in linking a small test C + + class with Go

If you wrap your C + + code with a C interface should is able to call your library with CGO (see the example of GMP in $G OROOT/MISC/CGO/GMP).

I ' m not sure if the idea of a class in C + + is really expressible in go, as it doesn ' t has inheritance.

Here's an example

I have a C + + class defined as

//FOO.HPPclassCxxfoo{ Public:  inta;Cxxfoo(int_a):a(_a){};  ~Cxxfoo(){};  void Bar();};//Foo.cpp#include <iostream>#include "FOO.HPP"voidCxxfoo::Bar(void){STD::cout<< This -a<<STD::Endl;}

Which I want to use in go. I ' ll use the C interface

//Foo.h#ifdef__cplusplusextern "C" {#endif  typedef void* Foo;  Foo Fooinit(void);  void Foofree(Foo);  void FooBar(Foo);#ifdef__cplusplus}#endif

(I use a void* instead of a C struct so the compiler knows the size of Foo)

The implementation is

//cfoo.cpp#include "FOO.HPP"#include "Foo.h"Foo Fooinit(){Cxxfoo*ret= NewCxxfoo(1);  return (void*)ret;}void Foofree(FooF){Cxxfoo*Foo= (Cxxfoo*)F;  DeleteFoo;}void FooBar(FooF){Cxxfoo*Foo= (Cxxfoo*)F;Foo -Bar();}

With all, and the go file is

//Foo.goPackage Foo//#include "foo.h"Import "C"Import "unsafe"typeGofoo struct {Foo C.Foo;}funcNew()(Gofoo){var retGofoo;ret.Foo=C.Fooinit();     returnret;}func(FGofoo) Free(){C.Foofree(unsafe.Pointer(F.Foo));}func(FGofoo)Bar(){C.FooBar(unsafe.Pointer(F.Foo));}

The makefile I used to compile this is

//MakefileTarg=Foocgofiles=Foo.Goinclude $(Goroot)/src/ Make.$(Goarch)include $(Goroot)/src/ Make.Pkgfoo.o:Foo.CPP G++ $(_cgo_cflags_$(Goarch)) -FPIC-O2-o $@-C $(Cgo_cflags) $<Cfoo.o:Cfoo.CPP G++ $(_cgo_cflags_$(Goarch)) -FPIC-O2-o $@-C $(Cgo_cflags) $<Cgo_ldflags+=-LSTDC++$(Elem)_foo. So:Foo.Cgo4.o foo.o cfoo.o gcc $(_cgo_cflags_$(Goarch)) $(_cgo_ldflags_$(GOOS)) -o $@ $^ $(Cgo_ldflags)

Try testing it with

  //foo_test.go  package foo  import     "testing"  func   Testfoo   ( t  *   Testing   t    foo  :=    Span class= "Typ" >new   ();   foo   bar   ();   foo   free   ();    }   

You'll need to install the shared library with make install and then run make test. Expected output is

GOTESTRM-F _test/Foo.a _gotest_.66g -o _gotest_.6Foo.Cgo1.go foo.Cgo2.Go foo_test.Gorm-F _test/Foo.Agopack GRC _test/Foo.a _gotest_.6Foo.Cgo3.61PASS