On Tue, 18 Apr 2017 18:09:03 -0700 (PDT)
hui zhang <fastfad...@gmail.com> wrote:
> > > c code
> > > string getstring() {...}
> > > go
> > > string gostr = ????(C.getstring())
> > Oh, and note that std::string is a fat object.
> >
> > So if getstring() really returns an instance of std::string,
> > and you need to actually extract its "raw bytes", you'd need to
> > call the c_str() method of std::string on that object before
> > applying the techniques from [1] to it.
> >
> > 1. https://github.com/golang/go/wiki/cgo#go-strings-and-c-strings
> >
> assume there is a c++ function string getpath()
> you mean I should do this ?
>
> char *CGetPath() {
> > auto str=getpath;
> > char *c = malloc(str.length()),
> > strcpy(c,str.c_str());
> > return c;
> > }
I beleive there's no need to do malloc() and copy the bytes over:
c_str () is defined to return to you a pointer to a contiguous array of
NUL-terminated representation of the string maintained by the
std::string instance. So you do (untested):
char *CGetPath() {
return getpath().c_str();
}
and then in your Go code you do
p := C.GoString(C.GetPath())
2. http://en.cppreference.com/w/cpp/string/basic_string/c_str
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