c++ hook PostMessage
时间: 2023-11-11 19:05:50 浏览: 43
The PostMessage function is a Windows API function that sends a message to the specified window or thread's message queue, without waiting for the recipient to process the message. This function is often used to send a message to a window to request that it perform a specific action or update its state.
A hook is a mechanism that allows an application to intercept and handle events or messages before they are processed by the target window or thread. A hook function can be installed to intercept PostMessage calls before they are sent to the target window or thread.
To install a hook for PostMessage, you can use the SetWindowsHookEx function with the WH_CALLWNDPROC hook type. This hook type allows you to intercept messages before they are processed by the target window's message queue. In the hook function, you can inspect the message and perform any necessary actions before passing it on to the target window.
Here is an example of a hook function for PostMessage:
```
LRESULT CALLBACK PostMessageHook(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode == HC_ACTION)
{
CWPSTRUCT* pMsg = (CWPSTRUCT*)lParam;
if (pMsg->message == WM_MY_CUSTOM_MESSAGE)
{
// Handle custom message here
return 0;
}
}
return CallNextHookEx(NULL, nCode, wParam, lParam);
}
```
In this example, the hook function intercepts messages with the custom message code WM_MY_CUSTOM_MESSAGE and handles them before passing them on to the target window. Note that the hook function must be installed using the SetWindowsHookEx function and must be removed using the UnhookWindowsHookEx function when it is no longer needed.