I have 3rd party static library.. It contains only (.h and .hpp) header files.. They are in C++ language.. But my project was in objective C. Can i use these libraries in my project and is it possible to call the c++ functions in my objective c project.. ???
Yes, you can do that. C++ is fully supported in Objective-C. Just rename the relevant Objective-C implementation files from .m to .mm, and they start to be compiled as C++ now, instead of “plain C mode.” These .mm files can directly call your C++ code.
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I am programming in Xcode in ObjC using a Cocoa static library built in c++ (built by me). For the library project, I made one public header(.hpp) that includes all the other header files(.hpp). Then in the ObjC project, I wrote a wrapper code(.hpp and .mm) to play as the interface, so it includes the public hpp header. To access the library, I then include the wrapper code in a normal m file. I believe all of these followed the tutorials, as it worked well for a few weeks.
However, after doing something stupid yesterday, the compiler for the ObjC project started to insist on building all the headers in ObjC. It first had problems with openCV packages in the c++ library, producing errors saying thoses are supposed to be built in c++ (as shown below). Even if I removed the openCV, the compiler cannot find any standard c++ libararies. I tried renaming the .hpp's to .h but it did not work.
Any suggestions on what I did wrong and how I can fix this?Much appreciated!
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Your errors are coming from compiling ImageProcessor.m. .m is the extension Obj-C files, so the compiler will try to compile it, and everything it includes as Obj-C.
I'd suggest renaming it to ImageProcessor.mm.
After learning more about header files, I realized what I did wrong: I included every header in the interface, so they are re-built every time outside the library, even if they are referenced by none-c++ code. The solution is to separate the interface header with other headers in the library completely.
I'm trying to add a C++ library to an iOS project. I added the source code files to the project, but seems like they are not interpreted like a C++ code.
For instance, I get the following error in a header file:
namespace soundtouch // Unknown type name 'namespace'
{
I already tried to change the type in the File inspector to "C++ Source" and "C++ Header" - nothing changed.
How can I import a C++ library to an XCode project?
C++ source files must have a recognised extension; .cpp, .cxx, .cc etc. and they will be compiled as C++ files. You shouldn't need to change the file type manually if the extension is correct (and recognised) when you add the file. The compilation language is determined on a per-module basis.
Intermixing C++ and Objective-C is a different story. There's a whole section in the ADC documentation on Objective-C++ (which uses the .mm extension). So if you want to call C++ code from Objective-C, it will need to be done from a .mm module.
Given the error you quoted, it looks like you're probably trying to include a C++ header file in an Objective-C module. To make this work, you need to rename the Objective-C module to .mm and then the compiler will treat it as Objective-C++.
It takes a little planning to determine a clean boundary between the C++ and Objective-C code, but it is worth some up-front thinking.
This article is worth reading:
Mixing Objective-C, C++ and Objective-C++
Every Objective-C implementation file (.m) that directly, or indirectly, #imports any of the C++ header files must be changed to an Objective-C++ implementation file by changing its file extension to .mm.
I am trying to using the CCfits library in an iOS project. CCfits is a C++ wrapper to the c library cfitsio.
I have the source code to both of these, and also have them built as static libraries (.a files). I would like to add the CCfits library (libCCfits.a) to an iOS project but when I am confused on how to access the library classes from my iPhone source files. I have the library added under "Link Binary with Libraries".
I understand that Xcode needs me to import a header file, but what is the proper way to attach the headers to the project? Do I need to make a framework file somehow? Or is the .a file enough?
You can easily mix C++ and Objective-C using Objective-C++. In XCode just rename your .m files to .mm and it will recognize the files as Objective-C++. Then you can use the C++ classes in your Objective-C code (some restrictions apply, but not many).
Since Objective-C is an extension to C you can use C libraries in any Objective-C program easily.
See https://stackoverflow.com/posts/10156243/edit
I have to create a iOS Programm using Code of some C++ POSIX Classes.
I already read the "Using C++ With Objective-C" manual of the Apple Developer Center.
They describe how to mix C++ & Objective C code in a .mm file.
My question is, is there any possibility to use the C++ Classes in my .h/.m files of a normal Objective C Project?
Or is it necessary to write the whole Project in that .mm file style with its own main?
You can combine in a project any types of files, say .c, .m, .cpp and .mm, and the compiler is chosen automatically depending on the extension. For example, you can keep the standard main.m file which comes with the XCode template, and add your new .h and .mm files to use Objective-C++.
In other words, there's no distinction between a normal Objective-C project and a Objective-C++ project. You just have to use .mm extension for the specific files which needs Objective-C++. This can be used in any project.
You have to force compilation of the Obj-C files in which you want to use C++ to Obj-C++ in the build menu. You can then create and use C++ objects in your Obj-C classes.
It depends on how you want to use the C++. In my projects I usually only make a few calls out to do some heavy lifting, etc.
What I do is have C++ in .cpp files, then create a few .mm files that have headers that have no C++ in them. These .mm files are obj-c wrappers for the C++. Then the C++ is 'contained' to the original posix files, plus a few files that give the C++ classes and calls all the interface you need. As few .mm files as possible is a good thing.
Keeping the C++ out of most of your code makes debugging, etc easier.
--Tom
Select Project directory in Xcode, In Build Settings tap, choose "Compile Sources As" is Objective-C++. No need change name type from .m to .mm.
Is there a way to include an objective-c header from a cpp? Because when I try to #include "cocos2d.h" from a cpp .h file, a lot of errors complaining about #'s and -'s are showing up.
Can c++ files include obj-c headers like that?
It is possible, but you need to use Objective-C++ (e.g. by making the file extension .mm) to mix the languages, plain C++ sources don't work.
To make that clear:
.m files only allow Objective-C sources
.cpp files only allow C++ sources
.mm allow mixed Objective-C++ sources - i.e. both Objective-C and C++ with some limitations
If you need to keep the two worlds seperated instead you need to write wrapper classes that hides the Objective-C details from C++ and vice versa.
C++ has no idea what Objective-C is. So including an Objective-C .h in a .cpp is a no-go.
The other way around, though is fine, if you use the .mm file extension (Objective-C++) instead of .m (Objective-C).
It is possible when you are compiling with mixed objc/c++. Cocoa applications can be written in languages mix in both directions: you can either use an obj-c class inside the C++ or a C++ class inside a obj-c object.
I assume in your case you are compiling pure C++ app where the obj-c code is not allowed.