一个简单的钩子安装问题

Question

我用：HHOOK  hook = NULL;
hook = SetWindowsHookEx(WH_JOURNALRECORD,
                        (HOOKPROC)KeyProc,
                        NULL,
                        GetCurrentThreadId()
                        );
if(hook == NULL)
{ 
   MessageBox("hook = null"); return FALSE;
}安装钩子函数keyproc，为什么总是  hook == NULL?

Answer 1

试一试：
hook = SetWindowsHookEx(WH_JOURNALRECORD,
                        (HOOKPROC)KeyProc,
                        GetCurrentThreadId()，
                        0
                        );

Answer 2

This is my SetWindowsHookEx-call:    HHOOK
hook=SetWindowsHookEx(WH_JOURNALRECORD,MMC_JournalRecordProc,NULL,0);
    ASSERT (hook!=NULL); //and this assertion fails