让一个DLL调用带函数指针的exe函数 [英] letting a DLL call a exe function with function pointer

问题描述

任何人都可以告诉我我做错了什么？
我试图在不同的线程上运行自定义main。

Can anyone tell me what I'm doing wrong? I'm trying to run a custom main on a different thread.

这是代码。

.exe

main.cpp

.exe
main.cpp

#include "dll_class.h"
#include <iostream>
int main(void);
DllClass object(main);
int main(void)
{
    std::cout << "Enter the main code.\n";
    std::getchar();
}

.dll

dll_class.h

.dll
dll_class.h

#include "platform.h"
#include <iostream>
class DLL_API DllClass //DLL_API is just a macro for import and export.
{
public:
    DllClass(int(*main)(void))
    {
        std::cout << "Start application.\n";
        platform = new Platform(main);
    }
    ~DllClass(void)
    {
        delete platform;
    }
private:
    Platform* platform;
};

platform.h

platform.h

class DLL_API Platform
{
public:
    Platform(main_t main_tp);
    ~Platform(void){}
};

platform.cpp

platform.cpp

#include "platform.h"
#include "Windows.h"
#include <iostream>

HHOOK hookHandle;
int(*main_p)(void);//This will hold a the main function of the the .exe.
LRESULT CALLBACK keyHandler(int nCode, WPARAM wParam, LPARAM lParam);

DWORD WINAPI callMain(_In_  LPVOID lpParameter)
{
    std::cout << "Calling the main function.\n";
    main_p();
    return 0;
}

Platform::Platform(int(*main_tp)(void))
{
    main_p = main_tp;
    CreateThread(NULL, 0, callMain, NULL, 0, NULL);
    std::cout << "Setting hooks.\n";
    hookHandle = SetWindowsHookEx(WH_MOUSE_LL, keyHandler, NULL, 0);
    std::cout << "Enter message loop.\n";
    MSG message;
    while(GetMessage(&message, (HWND)-1, 0, 0) != 0){
        TranslateMessage( &message );
        DispatchMessage( &message );
    }
}

LRESULT CALLBACK keyHandler(int nCode, WPARAM wParam, LPARAM lParam)
{
    std::cout << "Inside the hook function.\n" << std::endl;
    return CallNextHookEx(hookHandle, nCode, wParam, lParam);
}

它运行得很好，直到某一时刻。
这是输出。

It runs great, till a certain moment. This is the output.

Start application.  
Setting hooks.  
Calling the main function.  
Enter message loop.  
Inside the hook function. (A lot of times of course).  

但它从不说：

Enter the main code.

是不可能让dll调用exe函数？

Is it impossible to let dll call a exe function?

推荐答案

从共享库调用可执行文件中的函数非常可能。但是，如另一个答案中提到的C标准不允许调用 main 。这与C运行时（以防止语言律师：插入有时在这里）依赖于一定的顺序的事实，如果你尝试调用 main 在C运行时完成正确的初始化之前， main ，你会遇到问题。

It is very much POSSIBLE to call a function in the executable file from a shared library. However, the C standard, as mentioned in the other answer, doesn't allow you to call main. This has to do with the fact that the C runtime [to guard against language lawyers: insert "sometimes" here] relies on a certain order of things, and if you try to call main before the C runtime has done the right initialization BEFORE main, you get problems.

如果你的目标是实际上颠覆了 main ，那么你必须找到一种不同的方式这 - 至少如果你期望它工作于多个特定的可执行文件。

If your goal is to actually subvert what main does, then you will have to find a different way of achieving this - at least if you expect it to work for more than one particular executable.

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