Yep, stringWithUTF8String/UTF8String works well for std:string. I recommend
creating NSStringForStdString() and StdStringForNSString() utility
functions, and possibly an NSString category to add -stdStringValue.
-Rob
On Thu, Mar 20, 2008 at 4:05 PM, Jeff LaMarche <[EMAIL PROTECTED]>
wrote:
> What about the UTF8String method? It replaces the old lossyCString
> method and should give you a pointer to a c string
>
> Sent from my iPhone
>
> On Mar 20, 2008, at 3:34 PM, Jeremy <[EMAIL PROTECTED]> wrote:
>
> > Thanks everyone!
> > Using a void* for the member variable of my wrapper class did the
> > trick and I now have my Objective C code calling my C++ code!
> >
> > What is the best way to pass strings from my Objective C code to my C
> > ++ code though?
> > I started looking at the unichar definition and the methods on
> > NSString, but would like to know if there is an obvious standard for
> > dealing with the unicode issues.
> >
> >
> > On Mar 20, 2008, at 1:32 PM, Rob Napier wrote:
> >
> >> Say you have a C++ object called MyObject in the namespace myapp
> >> that you want to access through your ObjC. What I tend to do is
> >> create an ObjC++ object called MyObjectWrapper that owns a
> >> myapp::MyObject and presents a pure ObjC interface to its methods.
> >> Users of MyObjectWrapper don't have to include MyObject.h. The
> >> trick is that you need to use void* rather than a real class type
> >> in MyObjectWrapper.h like this:
> >>
> >> typedef void* MyObjectPtr
> >>
> >> @interterface MyObjectWrapper : NSObject
> >> {
> >> MyObjectPtr myObject;
> >> }
> >>
> >> That will get you around having C++ class definitions in your
> >> header. For a large system, hoist Wrapper into a superclass that
> >> can handle setting and releasing its owned object. This is also a
> >> good place to put routines to convert vectors and lists into
> >> NSArrays, and other similar handy routines.
> >>
> >> I still don't think ObjC++ is the best way to learn Cocoa. As has
> >> been discussed on this list before, the best way to learn Cocoa is
> >> in the language Apple uses and best documents. From there, ObjC++,
> >> RubyCocoa, etc are all useful tools for helping people who already
> >> understand ObjC.
> >>
> >> -Rob
> >>
> >> On Thu, Mar 20, 2008 at 12:40 PM, Jeremy <[EMAIL PROTECTED]> wrote:
> >> Thanks for the input guys, I really appreciate the help.
> >>
> >> I do have a lot of C++ code that I would like to use and put behind
> >> a Cocoa front end, so I think that using Objective C++ classes as
> >> wrapper classes around my C++ classes is the route I would like to
> >> take.
> >>
> >> Anyone have an example of such a wrapper class so I can get an idea
> >> of what is the preferred methodology?
> >> I'm guessing that you create an Objective C++ class with a member
> >> variable that is a C++ class and then mirror the methods from the C+
> >> + class?
> >>
> >> I'm worried that I'll still end up having to import the header file
> >> for my C++ class in my Objective C source file though, which caused
> >> a lot of compile errors previously.
> >>
> >>
> >> On Mar 20, 2008, at 12:32 PM, John Stiles wrote:
> >>> Without starting a religious war, I have to disagree with this.
> >>>
> >>> ObjC++ is probably a bad idea if you are a novice programmer in
> >>> general, but I think it also has some really good things going for
> >>> it, and having written huge amounts of ObjC++ code, I think it's
> >>> perfectly straightforward to use. It is by far your best bet for
> >>> writing cross-platform code that uses a native Cocoa front end.
> >>>
> >>>
> >>> Rob Napier wrote:
> >>>>
> >>>> On Wed, Mar 19, 2008 at 4:12 PM, Jeremy <[EMAIL PROTECTED]> wrote:
> >>>>
> >>>>> Hi.
> >>>>>
> >>>>> I am just starting to learn Cocoa and would like to use standard
> >>>>> C++
> >>>>> classes from my Objective C/C++ classes.
> >>>>>
> >>>> You really don't. You think you do (probably because you know C++),
> >>>> but then you enter the crazy messed up world of Objective-C++ and
> >>>> discover that you really wish you hadn't. A bit of an
> >>>> overstatement,
> >>>> yes, but really I'd recommend against using ObjC++ unless you have
> >>>> existing C++ code that you have to bridge to, and then it's best
> >>>> used
> >>>> just to wrap the C++ classes so that ObjC can deal with them. Learn
> >>>> Cocoa in pure ObjC.
> >>>>
> >>>> ObjC and C++ have very different models for managing memory, types,
> >>>> pointers and well, just about everything. Memory management in
> >>>> particular is a real hassle. ObjC++ strips away the safety nets
> >>>> from
> >>>> both ObjC and C++ because now you have to track two very different
> >>>> ways of managing memory (retain counting versus ref variables for
> >>>> instance).
> >>>>
> >>>>
> >>>>> Is there any known documentation on how to do this, or does anyone
> >>>>> have any pointers?
> >>>>>
> >>>>> I tried creating a new object of my C++ class and calling a
> >>>>> method on
> >>>>> it in a .m file and received a bunch of errors (including new not
> >>>>> being found).
> >>>>>
> >>>>> I then changed my .m file to a .mm file and all of the errors went
> >>>>> away except for one:
> >>>>> "cannot find interface declaration for 'MyClass'"
> >>>>>
> >>>> This probably means that ObjC expects there to be an ObjC class
> >>>> called
> >>>> MyClass (rather than a C++ class called MyClass; they're completely
> >>>> unrelated class structures). I suspect that you accidentally put
> >>>> "@class MyClass" somewhere rather than "class MyClass", or possibly
> >>>> wrote "@interface MyClass" somewhere. Alternately, you failed to
> >>>> put
> >>>> "class MyClass" above the declaration of m_pMemberVariable and so
> >>>> the
> >>>> compiler assumed MyClass was an ObjC class (this is less likely
> >>>> since
> >>>> you should have gotten a compiler error elsewhere for that error).
> >>>>
> >>>> I strongly recommend naming your ObjC and ObjC++ classes
> >>>> differently.
> >>>> I typically name the ObjC++ classes ending in "Wrapper" but that's
> >>>> because I only ever use these classes to wrap existing C++ classes
> >>>> defined in separate C++-only projects.
> >>>>
> >>>> Also, make sure that you're working in the right namespace. You may
> >>>> need to say "new myNamespace::MyClass" here.
> >>>>
> >>>> ObjC++ is deep magic. It is not a good place to learn Cocoa. It
> >>>> is a
> >>>> useful tool once you know Cocoa and need to integrate it at key
> >>>> points
> >>>> with C++.
> >>>>
> >>>> -Rob
> >> --
> >> Rob Napier -- Software and Security Consulting -- http://
> >> robnapier.net
> >> "Those who would give up essential liberty to purchase a little
> >> temporary safety, deserve neither liberty nor safety." -- B.
> >> Franklin, Printer
> >
> > _______________________________________________
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--
Rob Napier -- Software and Security Consulting -- http://robnapier.net
"Those who would give up essential liberty to purchase a little temporary
safety, deserve neither liberty nor safety." -- B. Franklin, Printer
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