| DWORD DefHookProc(nCode, wParam, lParam, lplpfnNextHook) | |||||
| int nCode; | /* process code | */ | |||
| DWORD wParam; | /* first message parameter | */ | |||
| LONG lParam; | /* second message parameter | */ | |||
| FARPROC *lplpfnNextHook; | /* not used | */ | |||
This function is obsolete but has been retained for backward compatibility with Windows version 3.0 and earlier. Applications written for Windows version 3.1 and later should use the CallNextHookEx function.
The DefHookProc function calls the next function in a chain of hook functions. A hook function is a function that processes events before they are sent to an application's message-processing loop in the WinMain function. When an application defines more than one hook function by using the SetWindowsHook function, Windows forms a linked list or hook chain. Windows places functions of the same type in a chain.
nCode
Specifies a code used by the Windows hook function (also called the message-filter function) to determine how to process the message.
wParam
Specifies additional message-dependent information.
lParam
Specifies additional message-dependent information.
lplpfnNextHook
This parameter is not used in Win32.
The return value specifies the result of the event processing and depends on the event.
SetWindowsHook, UnhookWindowsHook