使用C结构目标C [英] Use C Struct in Objective C

问题描述

在一个X code项目，我有功能的C文件，它编译和作品确定

In an Xcode project I have a C file with functions, it compiles and works OK

我要包我的C code在结构上，我怎么能叫他们在Objective-C？

I want to wrap my C code in struct(s), how will I be able to call them in Objective-C?

推荐答案

声明函数指针，将它们添加到您的结构，然后打电话给他们，这只是℃。

例如：

//Typedef 2 function pointers, first takes and returns int,
// second takes and returns double
typedef int    (*FuncPtrInt)   (int);
typedef double (*FuncPtrDouble)(double);

// create structure to store function pointers
struct ABC
{
    FuncPtrInt    applyA;
    FuncPtrDouble applyB;
};

// create some functions to use with structure
int incrFuncA(int num) { return ++num; }
double decrFuncB(double num) { return --num; }
double multiplyFuncB(double num) { return num*num; }

// try it out
void testStruct()
{
    struct ABC abc;
    abc.applyA = incrFuncA;
    abc.applyB = decrFuncB;

    NSLog(@"increment: %d",abc.applyA(3));
    NSLog(@"decrement: %f",abc.applyB(3.5));

    abc.applyB = multiplyFuncB;

    NSLog(@"multiply: %f",abc.applyB(3.5));
}

输出：

2010-02-01 10:36:22.335 x[11847] increment: 4
2010-02-01 10:36:22.336 x[11847] decrement: 2.500000
2010-02-01 10:36:22.336 x[11847] multiply: 12.250000

---

如果您想与那里的功能在结构上进行操作，你在默认情况下指针传递给函数功能结构（类似于C ++一样）：

---

If you want to have a struct with functions where functions operate on the structure you have to pass the pointer to that function by default (similar to what c++ does):

定义：

struct ClassABC;
typedef int (*FuncPtrClassABC)(struct ClassABC *);
typedef int (*FuncPtrClassABCInt)(struct ClassABC *, int);

int incrFunc(struct ClassABC * abc);
int decrFunc(struct ClassABC * abc);
int addFunc(struct ClassABC * abc, int num);
int subtractFunc(struct ClassABC * abc, int num);

struct ClassABC
{
    int i;
    FuncPtrClassABC    increment;
    FuncPtrClassABC    decrement;
    FuncPtrClassABCInt add;
    FuncPtrClassABCInt subtract;
};

正如你所看到的这些功能​​可以独立，你还是会通过ClassABC的：

As you can see these functions could be standalone, you would still pass the ClassABC in:

int incrFunc(struct ClassABC * abc) { return ++(abc->i); }
int decrFunc(struct ClassABC * abc) { return --(abc->i); }
int addFunc(struct ClassABC * abc, int num)
{ abc->i += num; return abc->i; }
int subtractFunc(struct ClassABC * abc, int num)
{ abc->i -= num; return abc->i; }

初​​始化帮手FUNC：

Initialization helper func:

void initClassABC(struct ClassABC * abc)
{
    abc->i = 0;
    abc->increment = incrFunc;
    abc->decrement = decrFunc;
    abc->add = addFunc;
    abc->subtract = subtractFunc;
}

用法：

struct ClassABC cabc;
initClassABC(&cabc);

cabc.add(&cabc,4);
NSLog(@"add: %d", cabc.i);

cabc.decrement(&cabc);
NSLog(@"decrement: %d", cabc.i);

cabc.subtract(&cabc,2);
NSLog(@"subtract: %d", cabc.i);

输出：

2010-02-01 10:56:39.569 x[12894] add: 4
2010-02-01 10:56:39.569 x[12894] decrement: 3
2010-02-01 10:56:39.569 x[12894] subtract: 1

欣赏

这篇关于使用C结构目标C的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！