在Xcode中使用C++与Objective-C混编
有时候,出于性能或可移植性的考虑,需要在iOS项目中使用到C++。
假设我们用C++写了下面的People类:
[cpp]
//
// People.h
// MixedWithCppDemo
//
// Created by Jason Lee on 12-8-18.
// Copyright (c) 2012年 Jason Lee. All rights reserved.
//
#ifndef __MixedWithCppDemo__People__
#define __MixedWithCppDemo__People__
#include <iostream>
class People
{
public:
void say(const char *words);
};
#endif /* defined(__MixedWithCppDemo__People__) */
[cpp] view plaincopy
//
// People.cpp
// MixedWithCppDemo
//
// Created by Jason Lee on 12-8-18.
// Copyright (c) 2012年 Jason Lee. All rights reserved.
//
#include "People.h"
void People::say(const char *words)
{
std::cout << words << std::endl;
}
然后,我们用Objective-C封装一下,这时候文件后缀需要为.mm,以告诉编译器这是和C++混编的代码:
[cpp]
//
// PeopleWrapper.h
// MixedWithCppDemo
//
// Created by Jason Lee on 12-8-18.
// Copyright (c) 2012年 Jason Lee. All rights reserved.
//
#import <Foundation/Foundation.h>
#include "People.h"
@inte易做图ce PeopleWrapper : NSObject
{
People *people;
}
- (void)say:(NSString *)words;
@end
[cpp] view plaincopy
//
// PeopleWrapper.mm
// MixedWithCppDemo
//
// Created by Jason Lee on 12-8-18.
// Copyright (c) 2012年 Jason Lee. All rights reserved.
//
#import "PeopleWrapper.h"
@implementation PeopleWrapper
- (void)say:(NSString *)words
{
people->say([words UTF8String]);
}
@end
最后,我们需要在ViewController.m文件中使用PeopleWrapper:
[cpp]
PeopleWrapper *people = [[PeopleWrapper alloc] init];
[people say:@"Hello, Cpp.\n"];
[people release], people = nil;
结果发现编译通不过,提示“iostream file not found”之类的错误。
这是由于ViewController.m实际上也用到了C++代码,同样需要改后缀名为.mm。
修改后缀名后编译通过,可以看到输出“
Hello, Cpp.
”。
补充:软件开发 , C++ ,