Could anyone define a C Macro for me?

[shagpg2008]

Could anyone define a C Macro that includes the following function:
there is one pointer pdata, which is a struct
struct _data {
int m1;
int m2;
};

fun()
{
....

//I can use MACRO anywhere in a function.
MACRO(_data, int m1, int m2)
{
//Here I can use m1 & m2 directly,
//but not ((struct _data*)pdata)->m1 & ((struct _data*)pdata)->m2.
//assigned: ((struct _data*)pdata)->m1 ---> m1;
// ((struct _data*)pdata)->m2 ---> m2;
printf("m1 = %d, m2 = %d", m1, m2);
}

}


How can I define the MACRO ??

Thank you very much!
Happy new year!

[shagpg2008]

自己顶下！呵呵

[拥剑公子]

/**
* container_of - cast a member of a structure out to the containing structure
*
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
* @member: the name of the member within the struct.
*
*/
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})


linux kernel里面的方法

[自信男孩]

[Quote=引用 2 楼 jinglexy 的回复:]
/**
* container_of - cast a member of a structure out to the containing structure
*
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
* @membe……
[/Quote]
++

[shagpg2008]

非常感谢您的回复！

可能是我没说清楚。

struct _data {
int m1;
int m2;
};


fun()
{
struct _data dt = {0, 1};
char * pdata = &dt;

.......

MACRO(_data, int m1, int m2) { //在这个宏里面完成各个赋值。
printf("m1 = %d, m2 = %d", m1, m2);
}

}

[shagpg2008]

如何实现这个宏：
MACRO

[aquanull]

如果要用这种语法通过m1、m2来修改dt.m1、dt.m2的值，需要C++的引用……

[iamnobody]

C is too week in handling this.
try C++;

[shagpg2008]

[Quote=引用 6 楼 aquanull 的回复:]

如果要用这种语法通过m1、m2来修改dt.m1、dt.m2的值，需要C++的引用……

and mingliang1212: try C++;
[/Quote]

if C++ will be OK, could you help me to define the MACRO ?
I think it over and over, but can't help.

[iamnobody]

template<typename Type,typename MemberType,MemberType Type::*pMember>
struct FillMember
{
	void operator()(Type &data,MemberType new_value)
	{
		data.*pMember = new_value;
	}
};
///////////////////////////
//what you need to do with it is the following;
struct TestStruct
{
	int x;
	char y;
};

//you need the following two objects to help 
FillMember<TestStruct,int,&TestStruct::x> fill_x;
FillMember<TestStruct,char,&TestStruct::y> fill_y;

#define FILL_TEST(test,x,y) \
	do{fill_x(test,x);fill_y(test,y);}while(0)
int main()
{

	//how to use:
	TestStruct test;
	fill_x(test,23);//fill x only;
	fill_y(test,'y');

	FILL_TEST(test,123,'a');//fill both;

	printf("filled test: x = %d, y = %c",test.x,test.y);
	getchar();
}

[shagpg2008]

谢谢你。 9楼

我要的不只是赋值，
宏的格式是：

MACRO(_data, int m1, int m2) {
.....
}

在宏里面实现对 m1, m2的赋值。注意， m1,m2是有类型的，是变量，不是常量。
Anyway, 还是谢谢你。

让大家一起来探讨吧！

[iamnobody]

//I try to use C to implement this
struct _data {
  int m1;
  int m2;
};


int __COUNT;
#define GET_MEMBER_POS(struct_type,member_name) (int)(&(struct_type*)0->member_name)
#define MACRO(pdata,mem1,mem2) \
	__COUNT = 1;\
	for(mem1 = pdata->m1; __COUNT;)\
		for(mem2 = pdata->m2; __COUNT;__COUNT--)

		
int main()
{

	//how to use:
	_data test;
	_data* pdata = &test;
	test.m1 = 12;
	test.m2 = 23;

	MACRO(pdata,int x,int y)
	{
		printf("test : m1 = %d,m2 = %d",x,y);

	}
	

	getchar();
}

[shagpg2008]

Oh, Great, very nice. mingliang1212 thank you very much for your tips.
And another thing: MACRO(pdata,int x,int y) is only one example, I'd like the MACRO is:

#define MACRO(pdata, ...)

So when we use it, MACRO(pdata,int x,int y) is an axample, and MACRO(pdata,struct _data x,char y) is anther axample. Though I know it's a very big challenge, Let's work it out.

Really big thanks to mingliang1212 .

[七十二寨寨主]

没看明白你什么意思
#和##不能解决你的问题吗？

[shagpg2008]

Ok, thank you for your tips. I can handle it now.
Thank you all again for the warm heart.
mingliang1212: 30
jinglexy : 10
Any Problem?

Thank you all again.

[iamnobody]

Come on,,,,

I don't wana try this with my poor C again..