回调函数(C/C++)

回调函数，就是自己写一个函数自己不调用，而是其他程序调用，下面举例exe调用dll函数，反过来，dll也调用exe函数，模拟杀毒软件查杀调用。

exe代码:

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>

using namespace std;

#define  Log(str) {{printf("[Kill]%s
",str);}}
typedef void(*pFunc)(DWORD addrFunc,char * msg);
typedef bool(*pFuncScan)();

pFunc dllCallBack;
pFuncScan dllScan;

void showResult(char * msg)
{
    Log(msg);
}

int main(int argc,char * argv[])
{
    HMODULE hDll = LoadLibrary("CallBackDll.dll");

    if (!hDll)
    {
        Log("LoadLibrary Failed");
        return 0;
    }

    dllCallBack = (pFunc)GetProcAddress(hDll, "RegCallBack");

    if (!dllCallBack)
    {
        Log("GetProcAddress Failed");
        return 0;
    }

    dllScan = (pFuncScan)GetProcAddress(hDll, "ScanVirus");
    dllCallBack((DWORD)showResult, "Main Virus");

    if (dllScan())
    {
        Log("Main Scan OK");
    }

    system("pause");
    return 0;
}

dll 代码:

#include <windows.h>
#include <stdio.h>

//Log Print
#define  Log(str) {{printf("[Kill]%s
",str);}}

//Function Pointer
typedef void (* pFunc)(char * argument);
char * argument = NULL;

pFunc callback;

//Register CallBack Function
extern "C" __declspec(dllexport) void  RegCallBack(DWORD addrFunc,char * msg)
{
    callback = (pFunc)addrFunc;
    argument = msg;
}

//Real Scan(Real Kill Function)
bool ScanMain()
{
    Log("Virus....");
    Sleep(1000);
    return true;
}

//Scan Show
extern "C" __declspec(dllexport) bool ScanVirus()
{
    Log("Scanning Begin...");
    Sleep(3000);

    if (ScanMain())
    {
        callback(argument);
        Sleep(1000);
    }

    Log("Scanning End...");

    return TRUE;
}

//Dll Main
BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        break;
    case DLL_THREAD_ATTACH:
        break;
    case DLL_THREAD_DETACH:
        break;
    case DLL_PROCESS_DETACH:
        break;
    }

    return TRUE;
}