Xcode 7 和 openCV（无 Swift）：Core.hpp 头文件必须编译为 C++
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Xcode 7 and openCV (no Swift): Core.hpp header must be compiled as C++
提问by mm24
I have followed the instructionson how to install OpenCV on an iOS project. However when using Xcode 7 I had to add manually a prefix header. Doing this unfortunately did not help and I was still getting compile errors. I then read another post suggesting that is best to add manually the imports and not use prefix headers in Xcode 7, so I did.
我已按照有关如何在 iOS 项目上安装 OpenCV的说明进行操作。但是，在使用 Xcode 7 时，我必须手动添加前缀标头。不幸的是，这样做没有帮助，我仍然遇到编译错误。然后我读了另一篇文章，建议最好手动添加导入，而不是在 Xcode 7 中使用前缀标头，所以我这样做了。
Here is my code:
这是我的代码：
#import "ViewController.h"
#import <opencv2/opencv.hpp>
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import <opencv2/highgui/cap_ios.h>
//using namespace cv;
@interface ViewController ()
{
IBOutlet UIImageView* imageView;
IBOutlet UIButton* button;
}
- (IBAction)actionStart:(id)sender;
@end
However I still get the following errors.
但是我仍然收到以下错误。
When I uncomment the using namespace cv; I get the following:
当我取消注释 using 命名空间 cv; 我得到以下信息：
I found some complex solutions talking about exposing headers to Swift etc.. I just want my project to work on Objective-C with Xcode 7 ...
我发现了一些关于向 Swift 公开标头等的复杂解决方案。我只是希望我的项目能够使用 Xcode 7 在 Objective-C 上工作......
回答by Petesh
OpenCV is a C++framework, which means that any code that makes use of OpenCV has to be compiled with C++interpretation, rather than Cinterpretation.
OpenCV 是一个C++框架，这意味着任何使用 OpenCV 的代码都必须通过C++解释来编译，而不是C解释。
The errors you see, e.g. with the using namespace cv;indicate that the code is compiled using the objective-C compiler, rather than the objective-C++ compiler.
您看到的错误，例如，using namespace cv;表明代码是使用目标 C 编译器而不是目标 C++ 编译器编译的。
As I mentioned in my comment the easiest way to get this to happen is to ensure that any file that #includes an opencv header must be named e.g. ViewController.mm, i.e. it must be an Objective-C++ file.
正如我在评论中提到的，最简单的方法是确保任何#include包含 opencv 头文件的文件都必须命名为 eg ViewController.mm，即它必须是一个 Objective-C++ 文件。
Alternatively, you can select and override the Typeof the file, by explicitly selecting the Objective-C++ Sourceoption for the file type in the utilities pane.
或者，您可以Type通过Objective-C++ Source在实用程序窗格中明确选择文件类型选项来选择和覆盖文件的。
回答by bRo
I just had the exact same problem. I'm working in a Swift project with OpenCV.
我只是遇到了完全相同的问题。我正在使用 OpenCV 参与一个 Swift 项目。
Regarding Swift, its entry point to OpenCV is a file I called OpenCVWrapper. So I got OpenCVWrapper.h and OpenCVWrapper.mm. In the bridging header of my project, I got #import "OpenCVWrapper.h".
关于 Swift，它对 OpenCV 的入口点是一个我称为 OpenCVWrapper 的文件。所以我得到了 OpenCVWrapper.h 和 OpenCVWrapper.mm。在我的项目的桥接头中，我得到了 #import "OpenCVWrapper.h"。
Thing is I wanted to write a class called MatUtils in Objective-C++ that I could call from OpenCVWrapper.mm. For them to be seeable in there, I had to put them in MatUtils.h.
事情是我想在 Objective-C++ 中编写一个名为 MatUtils 的类，我可以从 OpenCVWrapper.mm 调用它。为了让它们在那里可见，我不得不将它们放在 MatUtils.h 中。
Long story short, the mistake is that in OpenCVWrapper.h, I did #import "MatUtils.h". MISTAKE!!!! As OpenCVWrapper is in the bridging header, C++ is now reachable from Swift!
长话短说，错误在于在 OpenCVWrapper.h 中，我做了 #import "MatUtils.h"。错误！！！！由于 OpenCVWrapper 位于桥接头中，因此现在可以从 Swift 访问 C++！
Quick fix : #import "MatUtils.h" in OpenCVWrapper.mm!
快速修复：#import "MatUtils.h" in OpenCVWrapper.mm！
Cheers! bRo
干杯! 兄弟
