钩子初接触（十二）

方法7  :  ForegroundIdleProc Function

The ForegroundIdleProc hook procedure is an application-defined or library-defined callback function used with the SetWindowsHookEx function. The system calls this function whenever the foreground thread is about to become idle.

ForegroundIdleProc钩子子程是和SetWindowsHookEx方法一起使用的、程序定义的或者库定义的回调函数。当前台线程即将变成空闲时，系统将调用该方法。

The HOOKPROC type defines a pointer to this callback function. ForegroundIdleProc is a placeholder for the application-defined or library-defined function name. HOOKPROC类型定义了指向该回调函数的指针。ForegroundIdleProc是程序定义的或者库定义的方法名字。

Syntax 语法

DWORD CALLBACK ForegroundIdleProc(     

   int code,

    DWORD wParam,

    LONG lParam

);

Parameters 参数

code ：[in] Specifies whether the hook procedure must process the message. If code is HC_ACTION, the hook procedure must process the message. If code is less than zero, the hook procedure must pass the message to the CallNextHookEx function without further processing and should return the value returned by CallNextHookEx.

指定钩子子程是否必须处理消息。如果nCode是HC_ACTION，钩子子程就必须处理该消息。如果nCode小于0，钩子子程就必须将该消息传递给CallNextHookEx方法，自己对消息不做进一步处理，并且应该返回由CallNextHookEx方法返回的返回值。

wParam ：This parameter is not used. 未使用

lParam  ：This parameter is not used. 未使用

Return Value 返回值

If code is less than zero, the hook procedure must return the value returned by CallNextHookEx. If code is greater than or equal to zero, it is highly recommended that you call CallNextHookEx and return the value it returns; otherwise, other applications that have installed WH_FOREGROUNDIDLE hooks will not receive hook notifications and may behave incorrectly as a result. If the hook procedure does not call CallNextHookEx, the return value should be zero.

如果nCode小于0，钩子子程必须返回由CallNextHookEx返回的返回值。如果nCode大于等于0，强烈要求调用CallNextHookEx方法，并返回由它返回的返回值；否则，其他已经安装了WH_ CALLWNDPROCRET钩子的程序将收不到钩子通知，可能导致行为的错误。如果钩子子程没有调用CallNextHookEx方法,返回值应该是0。

Remarks 备注

An application installs this hook procedure by specifying the WH_FOREGROUNDIDLE hook type and the pointer to the hook procedure in a call to the SetWindowsHookEx function.

应用程序通过下面方式安装该钩子子程：指定WH_ FOREGROUNDIDLE钩子类型；在调用SetWindowsHookEx方法的函数中指向钩子子程的指针。