C#调用C/C++ DLL参数传递(2)

C#调用C/C++ DLL参数传递(二)

此次示例包含了常用类型参数的转换及传递包括

1) 基本类型：int, unsigned char, float, double等

2) 指针类型;

3) 引用

4) 一维数组、二维数组

5) 简单结构体

6) 结构体中包含数组

7) 字符串类型

8) bool类型

后续再进行其它类型的封装，如

9) 函数指针与回调函数

10) 类

下面结合代码对这些类型

1。创建一个C++ 动态链接库的工程

实现文件dlldemo.cpp，内容如下

#include <stdlib.h>
#include <iostream>
#include <cmath>
#include "dlldemo.h"

int __stdcall PassString(char* msg)
{
	std::cout<<"msg:"<<msg<<std::endl;
	return 0;
}

long double __stdcall Power(double x, int y)
{
	return pow(x, y);
}

double __stdcall GetDistance2D(Location p1, Location p2)
{
	return sqrt( (p1.x - p2.x)*(p1.x - p2.x) + (p1.y - p2.y)*(p1.y - p2.y) );
}

int __stdcall GetDistance1D(int x1, int x2)
{
	return abs(x1 - x2);
}

int __stdcall GetValues(int **values,int width, int height)
{
	if( values == NULL || *values == NULL)
		return -1;
	for(int i=0; i<width; ++i){
		for(int j=0; j<height; ++j){
			values[i][j] = i*j;
		}
	}

	return width * height;
}

int __stdcall CopyValues(int* dst, int* src, int length)
{
	if( dst == NULL || src == NULL || length < 0)
		return -1;
	memmove(dst, src, sizeof(int)*length);
	return length;
}

int __stdcall GetValue(int& dst)
{
	return dst = 0x1155;
}

int __stdcall CopyArray2D(unsigned char** dst, unsigned char** src, int m, int n)
{
	if(dst == NULL || src == NULL || m <= 0 || n <= 0)
		return -1;
	memmove(dst[0],src[0],m * n * sizeof(unsigned char));
	return m * n;
}

int __stdcall CopyPointerArray2D(unsigned char** dst, unsigned char** src, int m, int n)
{
	if(dst == NULL || src == NULL || m <= 0 || n <= 0)
		return -1;
	for(int i=0; i<m; ++i){
		for(int j=0; j<n; ++j){
			dst[i][j] = src[i][j];
		}
	}
	return m * n;
}

bool __stdcall GetPerson(Person* p, char* name)
{
	if( name == NULL || p == NULL)
		return false;
	p->age = sizeof(bool);
	p->age = 100;
	strcpy(p->name, "Steve Jobs");
	strcpy(p->email, "Steve.Jobs@apple.com");
	p->isFemale = 0;
	return true;
}

int __stdcall SetEnable(bool enabled)
{
	return enabled;
}

头文件dlldemo.h内容如下：

#ifndef DLLDEMO_H_H
#define DLLDEMO_H_H

extern int __stdcall GetValues(int **values,int width, int height);
extern int __stdcall PassString(char* msg);
extern long double __stdcall Power(double x, int y);


struct Location{
	int x;
	int y;
};
double __stdcall GetDistance2D(Location p1, Location p2);
int __stdcall GetDistance1D(int x1, int x2);

extern int __stdcall CopyValues(int* dst, int* src, int length);

extern int __stdcall GetValue(int& dst);

extern int __stdcall CopyArray2D(unsigned char** dst, unsigned char** src, int m, int n);

extern int __stdcall CopyPointerArray2D(unsigned char** dst, unsigned char** src, int m, int n);

struct Person{
	char name[20];
	unsigned char age;
	bool isFemale;	// can NOT be bool
	char email[50];	
};

extern bool __stdcall GetPerson(Person* p, char* name);

extern int __stdcall SetEnable(bool enabled);

#endif

因为要导出函数，还要创建一个导出文件dlldemo.def

LIBRARY dlldemo
EXPORTS
GetValues
PassString
Power
GetDistance1D
GetDistance2D
CopyValues
GetValue
CopyArray2D
CopyPointerArray2D
GetPerson
SetEnable

因为C++函数实际生成的名称与我们看到的名称是不一样的，所以直接在C++代码中使用__declspec(dllexport) 导出的函数在C#中找不到，需要用.def文件来实现。

C#调用C/C++ DLL参数传递(2)

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