VC中通过修改注册表来修改Path后的奇怪问题

使用VC里修改注册表的API修改了：
HKEY_CURRENT_USER\Environment\Path
HEKY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment\Path

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加上这几句
Dword dwResult=0;
PostMessage(HWND_BROADCAST, WM_SETTINGCHANGE , NULL, NULL);
SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE , NULL,
(LPARAM)"Environment",SMTO_NORMAL, 1000, &dwResult);
SendMessageTimeout(HWND_BROADCAST,
WM_SETTINGCHANGE , NULL, (LPARAM)"Environment", SMTO_NOTIMEOUTIFNOTHUNG,1000, &dwResult);

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::SendMessage(HWND_BROADCAST,WM_SETTINGCHANGE,0,(LPARAM)TEXT("Environment"));
加上这句就行了。