c++ hook PostMessage
时间: 2023-11-11 11:05:53 浏览: 42
The PostMessage function is a Windows API function that allows an application to post a message to a thread's message queue. The message can be sent to either the same thread or a different thread, and can contain a user-defined message code and optional parameters.
To hook PostMessage, you would need to intercept the function call and modify its behavior. This can be done using a technique called function hooking, which involves replacing the original function with your own implementation.
Here is an example of how to hook PostMessage using the Detours library:
```
#include <Windows.h>
#include <detours.h>
// Define a type for the original PostMessage function
typedef BOOL(WINAPI *PostMessageFunc)(HWND, UINT, WPARAM, LPARAM);
// Define a pointer to the original PostMessage function
PostMessageFunc OriginalPostMessage = NULL;
// Implement your own version of the PostMessage function
BOOL WINAPI MyPostMessage(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{
// Do something before calling the original function
...
// Call the original function
BOOL result = OriginalPostMessage(hWnd, Msg, wParam, lParam);
// Do something after calling the original function
...
return result;
}
// Hook the PostMessage function
BOOL HookPostMessage()
{
// Get a pointer to the original function
OriginalPostMessage = (PostMessageFunc)GetProcAddress(GetModuleHandle("user32.dll"), "PostMessageA");
if (OriginalPostMessage == NULL)
return FALSE;
// Hook the function using Detours
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourAttach(&(LPVOID&)OriginalPostMessage, MyPostMessage);
DetourTransactionCommit();
return TRUE;
}
// Unhook the PostMessage function
VOID UnhookPostMessage()
{
// Unhook the function using Detours
DetourTransactionBegin();
DetourUpdateThread(GetCurrentThread());
DetourDetach(&(LPVOID&)OriginalPostMessage, MyPostMessage);
DetourTransactionCommit();
}
// Example usage
int main()
{
HookPostMessage();
// Call PostMessage as usual
PostMessage(hWnd, WM_MY_MESSAGE, wParam, lParam);
UnhookPostMessage();
return 0;
}
```
In this example, the MyPostMessage function is called instead of the original PostMessage function when it is hooked using Detours. The original function is called within MyPostMessage using the OriginalPostMessage pointer. Any modifications to the behavior of the function can be made within MyPostMessage before and after calling the original function.