I have a simple (and also trivial) banking application that I wrote in C++. I'm on ubuntu so I'm using GNOME (GTK+). I was wondering if I could write all my GUI in C/GTK+ and then somehow link it to my C++ code. Is this even possible?
Note: I don't want to use Qt or GTKmm, so please don't offer those as answers.
Yes, it's a very easy thing to do. All you have to do is expose some of the C++ functions as "extern C" so that the event handlers and callbacks in your UI code can call them.
In the case that you can't change the existing C++ source - no problem. just write a C++ shim for your UI, extern those functions, and call backend functions from there.
I don't see why not, with appropriate extern "C" usage so your C code can call into C++. Now, granted, you're probably making it a bit harder on yourself, but it's theoretically sound.
Like others propose you can write a C wrapper for your C++ library. But you can also write the front-end in C++, even if you only use the C subset. I can understand if you don't like the language mixing, but it is the easiest way, because you save the time to write the wrapper.
How about using wxWidgets instead?
You can just compile your GTK/C code as C++ without using GTKmm, and use the C++ code natively.
Most sane C libraries can be used from native C++ code, and GTK+ is fundamentaly a C library.
Related
With native c++, I mean, not managed c++, not cli, not any special things from microsoft, I can:
1) get high performance
2) use existing c++ code library and engine
3) write cross platform code (for example, for ios and android)
it needn't be fully native c++, I can use managed code to do the ui things, like object-c in ios and java in android, but beside interface, can I use native c++ code?
I suggest you have a look at the presentation here: Using the Windows Runtime from C++ and especially at the comments from Herb Sutter. I quote:
Please answer this question: If I decide to write C++ GUI application
in Metro style am I forced to use all these proprietary ref, sealed,
^, Platform::String^ extensions for GUI components or not?
#Tomas: No, you are not forced to use them. We are providing two
supported ways:
1) These language extensions (C++/CX).
2) A C++ template library (WRL), see
Windows Kits\8.0\Include\winrt\wrl as Yannick mentioned. WRL is a C++
library-based solution sort of along the lines of ATL, which offers
what I think you're looking for -- template wrapper/convenience
classes and explicit smart pointers and such.
Yes you absolutely can, real native C++ is fully supported.
You do however mostly have to use the new WinRT libraries to do an user interface or system calls and although they are native code and fully callable from C++ directly the interface to them makes it very painful indeed to do so, as everything is a reference counted COM object and in addition it's not so easy to create instances of them as just calling "new" so you have to write a lot of ugly code to do so.
As the earlier answer said, microsoft provide two ways to help with this. One is via language extensions to c++ and the other is a c++ template library. Personally I consider both to be rather ugly for doing something as simple as calling an API but that's just me :)
But to answer your question, it's completely possible to write your application in real native c++. You won't need to use managed code at all for anything. But you'll probably want to use either the language extensions or the template library to make calling the API more easy.
Personally I'm hoping someone writes a wrapper for WinRT that exposes the most necessary functionality as a more usable c++ native library and then everyone can just use that from c++ instead...
I have a C++ program that I wrote, and I would like to give it a user interface. Is there any way I can run a C++ program and put the information from the program onto the UI of a VB Application?
Sure.
Use
COM
COM Interop
P/Invoke (a.k.a. Declare in VB)
Oh, I forgot: C++/CLR if you intend to use Windows only
I suggest you write the whole application in a managed language (e.g. VB.Net) and only invoke C++ library functions for the performance critical work (or for legacy code that you already have, of course).
I think the easiest solution would be to put your C++ code into a DLL, and call your code from VB. Have a look at this article for more information...
http://www.codeproject.com/kb/DLL/XDllPt1.aspx
you can mix C++ and .NET
easiest is if you target your C++ code to the CLR, but you can also mix .NET and native code.
either way you basically make your C++ program a library your VB code can use.
I would like to create a portable library for iPhone, that also could be used for other platforms.
My question is the fallowing:
Does anyone knows what is the best to be used on the iPhone: Objective-C or Objective-C++? Does it works with C++ the same way as Objective-C with C or not?
Reasons: Objective-C is a superset of C, but Objective-C++ is not a superset of C++.
Thanks in advance!
UPDATE: What about memory usage, speed in the same implementation of an use case?
UPDATE1: If anyone can provide any more information, he'll be welcome.
If you're writing a portable library, and don't need specific language features for it, why not write it in straight C? It can be easily called from C++, C, Objective-C, and many, many other languages.
If you require specific language features that aren't available in C, you should tell us what they are so you can get better advice =)
I believe your information is incorrect. Objective-C++ is a superset of C++. Any C++ is legal Objective-C++. In addition, you can mix Objective-C and C++ code in an Objective-C++ (usually .mm) file and (with some restrictions) mix Objective-C and C++ class instance variables within an Objective-C++ class. Objective-C++ is particularly useful for interfacing between Objective-C and a C++ library. Write your cross-platform library in C++. You can then call it from Objective-C++ within an application. Re-read the Objective-C++ section of the Objective-C language guide for more info.
The major downside to using Objective-C++ is increased compile times (Objective-C++ is even worse than C++ and the Clang LLVM compiler doesn't handle Objective-C++ yet). There is no performance difference between Objective-C and Objective-C++ beyond any differences in the code that's called (e.g. if you're a better C++ dev., your C++ will probably be more efficient than your C library and visa versa).
They're not really different languages. Objective-C++ is just Objective-C with slightly limited support for including C++ code. Objective-C is the standard dialect, but if you need to work with C++, there's no reason not to use it. AFAIK, the biggest practical difference (aside from allowing use of different libraries) is that Objective-C++ seems to compile a bit slower. Just be sure to read up on it first if you do decide to go that route, because the merging of C++ and Objective-C is not 100% seamless.
If you are going to use this library on platforms other than the iPhone and Mac OS, you should use C++. If you plan only to port it to Mac OS, then go ahead and use Objective-C. Objective-C++ is just a way to integrate existing C++ code into Objective-C projects. Thus, you would not write a library in it. You might, however, use Objective-C++ to use this library from an iPhone or Mac project.
The truth is you can use C or C++ in Xcode. The reason to use Objective C for Cocoa and Cocoa Touch (iphone) is because of it's ease of use and how it handles many of the memory issues you would come across on it's own. Objective C and Xcode work like a dream. I would also recommend checking out http://www.kevincallahan.org/software/accessorizer.html
Accessorizer is amazing and cuts development time into nothing.
Having said that I see no problem in writing functions/methods in C or C++ and using them within a part of your XCode project. Just do not expect to use Objective C to play as nicely on other platforms. Apple and Windows development IDE's are different and Microsoft has a nice habit for not making things as compatible with other environments (not just Apple.)
I am glad to hear someone out their trying to reuse their code for other projects : ) Too many people forget to create their own libraries these days and I haven't the slightest idea why.
I hope this helps. Cheers,
Matthew
Here is your caveat: Spend the hundred on becoming a developer and launch xcode the IDE you will be working with on the Mac - this would be the best way for you to decide as it is apparent that you do not fully understand how this platform works at all.
Please don't be rude to everyone trying to help you. This community is built on respect. The people here really actually do help out and care and there are few places like this on the net left.
Go for C or C++ - I do not see any reason for recommending one over the other without knowing more about your goals.
In terms of memory usage, C++ and C do demand more disciplined coding. In terms of speed, C and C++ will in virtually any case be faster than any ObjC/ObjC++ solution. I do frequently mix my Objective C applications with C and C++ code and was always pleased with the results. As Jonathan correctly stated, ObjectiveC++ is mostly a bridge for using C++ code/libraries within your Objective C application/s.
You can freely use C++ objects from within Objective C++. You can however NOT use Objective C/C++ objects within C++. So its a one-way-road. To overcome any limitations imposed by this restriction, simply wrap your C++ objects with Objective C++ classes where needed.
"Objective-C is a strict superset of C, and Objective-C++ is a strict superset of C++." - https://developer.apple.com/library/mac/documentation/DeveloperTools/Conceptual/CppRuntimeEnv/Articles/SymbolVisibility.html
I am an experienced C/C++ developer but I am a novice in Ruby.
How can I call a C++ function from with in Ruby?
You have 3 possibilities :
1) Ruby is able to load libraries. Even if it is a bit tricky, you can decide to write your own loader and bind your C++ library in Ruby.
This is done using what is called an extension module. You will find a comprehensive tutorial here: http://www.rubyinside.com/how-to-create-a-ruby-extension-in-c-in-under-5-minutes-100.html
2) You can use a tool that will generate the Ruby wrapper around your C++ library. Look at SWIG for example (http://www.swig.org/).
You just have to create a file in a swig-specific syntax and provide it to SWIG. It will then be able to generate the wrapper for many languages, Ruby included.
3) You can choose to use a middleware, such as CORBA/ICE/whatever. It may be a bit overkill if you only want to call some C++ functions, but it will allow you to remote call the functions, or "hide" a grid behind the middleware.
To call C++ code from Ruby, you will likely want to build an extension.
If you are an experienced C++ developer, you may feel comfortable with Rice:
https://github.com/jasonroelofs/rice
It uses C++ metaprogramming techniques to simplify writing extensions.
If you were calling into C, you could also use ffi. Calling C++ code is a little more complicated than calling C code due to name mangling and exceptions.
I believe the questioner is asking how to call C++ from with in Ruby, if so then the for simple C/C++ RubyInline1 is by the far the simplest solution.
Alternatively if you need to call more substatntial C++ code, you can build a ruby extension. Here is a good tutorial
You need to wrap your c++ code in a C interface and then bind those C functions to ruby methods using rb_define_method()
alternatively you can use SWIG, as Aurelien said.
I'm writing a graphical application using Objective-C for the front end and C++ for the graphics processing and network communication. I read around on Apple's site looking for a way to link either a .dylib or .so with my C++ code in it to my Xcode project, but nothing seemed to work. I was able to get the project to reference it and link against it, but when I tried to call functions from that .dylib, it was saying that it didn't know what I was trying to do. Does anyone know what is going on here?
I know that Objective-C has all the libraries I would need to do graphics and networking, but I just feel like doing it like this. I haven't done much C++ in a while and I want to learn more Objective-C, so what better way than to use them together?
Thanks,
Robbie
Most of the projects I work on have an ObjC frontend and C++ backend. If you're dealing exclusively with functions, then Dave Gamble's name mangle fix is correct, but if you're dealing with more complex situations, where you need to deal with both ObjC and C++ objects, your best bet is to wrap the C++ objects in ObjC objects. Using opaque references (which is a very fancy way of saying void*), you can actually hand around C++ objects in ObjC and vice versa. I have some sample code that may be helpful.
That said, for graphics you're probably going to take a serious performance hit doing custom C++ rather than using Core Image and the related frameworks. Core Image and the other graphics frameworks are highly optimized for the Mac, and you're very unlikely to do better with hand-rolled C++ (or even very well-written C++ that isn't specifically for the Mac). As you move to 10.6 and grand central dispatch, the performance difference is going to be even more notable because you'll lose all the parallelization advances that you would get for free otherwise. This has nothing to do with ObjC; Core Image is C. You can call it from C++ all you like. I just recommend against custom graphics processing on Mac in any language unless you need portability or you have the expertise necessary to beat Core Image.
You're going to hit one obstacle in the form of what's called "name mangling". C++ stores function names in a way not compatible with Obj-C.
Objective-C doesn't implement classes in the same way as C++, so it's not going to like it.
One way around this is to implement a set of simple C functions which call the C++ functions. It'll be a good challenge to keep the number of C functions as low as possible! You'll end up with a nice compact interface! :)
To declare these functions in a C++ file, you'll need to mark them as C with:
extern "C" int function_name(char *blob,int number, double foo) {...}
This disables the standard name-mangling.
Build a header file with the prototypes for all these functions that you can share with your objective C code.
You won't be able to pass classes around in the same way (because your ObjC code can't use them), but you'll be able to pass pointers (although you might have to lie about the types a little).