objective-c - oc, c++混编，c++函数中如何识别self?

Question

一个项目，用到了opencv库，有一个代理方法,这里假设为void cPlusPlusMethod()，在这个函数中要调用[self test1];但是在这个函数中无法识别self.如何解决？
以下是代码：

#import "ViewController.h"
#include <fstream>

using namespace std;
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

 
}
void cPlusPlusMethod() {
    //在C++这个代理方法中 ，要运行 用oc写的类方法：[self test1];
    [self test1];//不识别self如何解决？
}
- (void) test1 {
    NSLog(@"test1 ");
}

@end

Answer 1

That is not called a proxy method, it should be called a callback function.

C functions are placed in the code area of ​​​​the memory when running, so if you want to access OC objects, you need to pass parameters or access global variables.

#import "ViewController.h"
#include <fstream>

using namespace std;
static ViewController *handle;

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    handle = self;
}

void cPlusPlusMethod() {
    [handle test1];
}

- (void)test1 {
    NSLog(@"test1 ");
}

- (void)dealloc {
    handle = NULL;
}

@end