我能在相同的Xcode项目中使用Swift、Objective-C、C和c++文件吗?

Can all 4 languages be used in the same project at all, and if so how?

所有4种语言都可以在同一个项目中使用吗?

There are similar questions in the flavor: Can I mix Swift with C++? Like the Objective - C .mm files to which the accepted answer is no.

味道中也有类似的问题:我能把Swift和c++混在一起吗?就像Objective - C .mm文件一样，接受的答案是no。

Using Bridging Header adequately, .h that do not contain C++ statements, Objective-C wrappers when .h do contain C++, .mm files to do the actual wrapping of C++ classes, and .swift, can the 4 languages (5 if you include Objective-C++) build and link into a single executable?

充分使用桥接头、不包含c++语句的.h、当.h包含c++时的Objective-C包装器、用于实际包装c++类的.mm文件和.swift，这四种语言(如果包含Objective-C++)能否构建并链接到单个可执行文件中?

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objective-c++xcode

objective - c + + xcode

1 个解决方案

#1

YES.

You can mix Swift, C, C++, Objective-C & Objective-C++ files in the same Xcode project.

您可以在同一个Xcode项目中混合使用Swift、C、c++、Objective-C和objective - c++文件。

C

// Declaration: C.h
#ifndef C_h
#define C_h
#ifdef __cplusplus
extern "C" {
#endif
    void hello_c(const char * name);
#ifdef __cplusplus
}
#endif
#endif /* C_h */

// Definition: C.c
#include "C.h"
#include <stdio.h>
void hello_c(const char * name) {
    printf("Hello %s in C\n", name);
}

C++

// Declaration: CPP.hpp
#pragma once
#include <string>
class CPP {
public:
    void hello_cpp(const std::string& name);
};

// Definition: CPP.cpp
#include "CPP.hpp"
#include <iostream>
using namespace std;
void CPP::hello_cpp(const std::string& name) {
    cout << "Hello " << name << " in C++" << endl;
}

Objective-C wrapper for C++

// Declaration: CPP-Wrapper.h
#import <Foundation/Foundation.h>
@interface CPP_Wrapper : NSObject
- (void)hello_cpp_wrapped:(NSString *)name;
@end

// Definition: CPP-Wrapper.mm
#import "CPP-Wrapper.h"
#include "CPP.hpp"
@implementation CPP_Wrapper
- (void)hello_cpp_wrapped:(NSString *)name {
    CPP cpp;
    cpp.hello_cpp([name cStringUsingEncoding:NSUTF8StringEncoding]);
}
@end

Objective-C

// Declaration: Objective-C.h
#import <Foundation/Foundation.h>
@interface Objective_C : NSObject
- (void)hello_objectiveC:(NSString *)name;
@end

// Definition: Objective-C.m
#import "Objective-C.h"
@implementation Objective_C
- (void)hello_objectiveC:(NSString*)name {
    printf("Hello %s in Objective-C\n", [name cStringUsingEncoding:NSUTF8StringEncoding]);
}
@end

Objective-C++

// Declaration: Objective-CPP.h
#import <Foundation/Foundation.h>
@interface Objective_CPP : NSObject
- (void)hello_objectiveCpp:(NSString *)name;
@end

// Definition: Objective-CPP.mm
#include <iostream>
#import "Objective-CPP.h"
using namespace std;
@implementation Objective_CPP
- (void)hello_objectiveCpp:(NSString *)name {
    cout << "Hello " << [name cStringUsingEncoding:NSUTF8StringEncoding] << " in Objective-C++\n";
}
@end

Swift

// Declaration & definition: Swift.swift
func hello_swift(_ name: String) {
    print("Hello \(name) in Swift")
}

Bridging-Header.h

Cannot import CPP.hpp header file, not because of it's naming convention, but because it contains the class keyword.

不能导入CPP。hpp头文件，不是因为它的命名约定，而是因为它包含类关键字。

#import "C.h"
#import "CPP-Wrapper.h"
#import "Objective-C.h"
#import "Objective-CPP.h"

Invocation from Swift

// Invoke C
hello_c("World".cStringUsingEncoding(NSUTF8StringEncoding))

// Can't Invoke C++ without a wrapper
// CPP().hello_cpp("World".cStringUsingEncoding(NSUTF8StringEncoding))
// Invoke C++ through Objective-C
CPP_Wrapper().hello_cpp_wrapped("World")

// Invoke Objective-C
Objective_C().hello_objectiveC("World")

// Invoke Objective-C++
Objective_CPP().hello_objectiveCpp("World")

// Invoke Swift
Swift().hello_swift("World")

.h (Headers)

(See item 3 in this Stack Overflow answer)

(见此堆栈溢出答案中的第3项)

.h: this is the tricky part, since they are ambiguously used for all flavors of C, ++ or not, Objective or not. When a .h does not contain a single C++ keyword, like class, it can be added to the ...Bridging-Header.h, and will expose whatever function the corresponding .c or .cpp functionalities it declares. Otherwise, that header must be wrapped in either a pure C or Objective-C API.

h:这是比较棘手的部分，因为它们在C、+或not、Objective或not中都有含糊的用法。当.h不包含单个c++关键字(如class)时，可以将其添加到…Bridging-Header中。h，并将暴露它声明的相应的.c或.cpp函数的任何函数。否则，该头必须封装在纯C或Objective-C API中。

Output

Hello World in C
Hello World in C++
Hello World in Objective-C
Hello World in Objective-C++
Hello World in Swift

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Comments

评论

Cy-4AH:

Cy-4AH:

Yes. You only need wrap C++ into C or Objective-C to use in Swift.

是的。您只需要将c++包装成C或Objective-C就可以在Swift中使用。

Tommy

汤米

Indeed, I have a project that does exactly that. C++ for the thrust of the abstract cross-platform model stuff with some C parts underneath; Objective-C to wrap the C++ classes for Swift purposes, Swift to bind all that to a subclass of NSDocument, with some custom views that interrogate the C stuff.

事实上，我有一个项目就是这么做的。c++用于抽象的跨平台模型的推进，下面有一些C部分;Objective-C为了快速的目的包装c++类，Swift将所有这些绑定到NSDocument的子类，并使用一些自定义视图来查询C内容。

MaddTheSane

MaddTheSane

Added the extern "C" wrapper as per your excellent suggestion. To invoke the C method void hello_c(const char * name) from C++ method hello_cpp(const std::string& name), add #include "C.h" and call hello_c(name.c_str());.

根据你的优秀建议添加外包装“C”包装。要从c++方法hello_cpp(const std::string& name)调用C方法void hello_c(const char * name)，添加#include“C”。h”和调用hello_c(name.c_str());。

Keith Adler

基思•阿德勒

The new SO-32541268: Now with parameters!

新的SO-32541268:现在有了参数!

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► Find this solution on GitHub and additional details on Swift Recipes.

►GitHub上找到这个解决方案和额外的细节迅速食谱。