【WM】应用程序实现网络去附着(unregister)的简便方法

在Windows Mobile下，应用程序如果需要网络去附着一般需要调用RIL函数RIL_UnregisterFromNetwork（调用扩展TAPI函数lineUnregister的很少见）。但是，由于该函数是异步的，如果想通过result callback获知网络去附着是否成功的话就比较麻烦了。

 

因此，笔者在此介绍一个未归档的函数UnregisterFromNetwork，该函数亦可实现网络去附着功能，其函数原型如下：

 

//  *************************************************************************
//  UnregisterFromNetwork
//
//  Purpose:
//      Unregisters the radio module from the network if it is
//      possible to do so, and waits for that operation to complete.
//
//  Returns:
//      HRESULT
//
//  *************************************************************************
HRESULT WINAPI UnregisterFromNetwork();

 

开发者如果要链接该函数需要使用导入库ccoreutl.lib。

 

以下是根据笔者反汇编所得，改用C/C++描述的UnregisterFromNetwork函数实现：

struct RIL_RESULT_Callback_Data { HANDLE hRILCallRetured; HRESULT hrRILResult; LPVOID lpData; DWORD cbData; }; VOID RIL_RESULT_Callback(DWORD dwCode, HRESULT __formal, CONST VOID* lpData, DWORD cbData, DWORD dwParam) { RIL_RESULT_Callback_Data *prilrcd = (RIL_RESULT_Callback_Data *)dwParam; prilrcd->hrRILResult = E_FAIL; LocalFree(prilrcd->lpData); prilrcd->lpData = NULL; prilrcd->cbData = 0; if (dwCode == RIL_RESULT_OK) { prilrcd->hrRILResult = S_OK; if (cbData && lpData) { prilrcd->lpData = LocalAlloc(LMEM_FIXED, cbData); if (prilrcd->lpData) { memcpy(prilrcd->lpData, lpData, cbData); prilrcd->cbData = cbData; } } } else if ((dwCode == RIL_RESULT_ERROR || dwCode == RIL_RESULT_NODIALTONE) && lpData) { prilrcd->hrRILResult = *(HRESULT *)lpData; } SetEvent(prilrcd->hRILCallRetured); } HRESULT UnregisterFromNetwork() { HRESULT hr = E_FAIL; HMODULE hModule = LoadLibrary(TEXT("ril.dll")); if (!hModule) { return hr; } PRIL_INITIALIZE pfnInitialize = GetProcAddress(hModule, TEXT("RIL_Initialize")); PRIL_DEINITIALIZE pfnDeinitialize = GetProcAddress(hModule, TEXT("RIL_Deinitialize")); PRIL_UNREGISTERFROMNETWORK pfnUnregister = GetProcAddress(hModule, TEXT("RIL_UnregisterFromNetwork")); if (pfnInitialize && pfnDeinitialize && pfnUnregister) { HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, NULL); if (hEvent) { RIL_RESULT_Callback_Data rilrcd; rilrcd.hRILCallRetured = hEvent; rilrcd.hrRILResult = S_OK; rilrcd.lpData = NULL; rilrcd.cbData = 0; HRIL hRIL; if (SUCCEEDED(pfnInitialize(1, RIL_RESULT_Callback, NULL, 0, rilrcd, &hRIL))) { if (SUCCEEDED(pfnUnregister(hRIL))) { DWORD rc = WaitForSingleObject(rilrcd.hRILCallRetured, INFINITE); if (rc == WAIT_OBJECT_0 && SUCCEEDED(rilrcd.hrRILResult)) { hr = S_OK; } } pfnDeinitialize(hRIL); } CloseHandle(hEvent); LocalFree(rilrcd.lpData); rilrcd.lpData = NULL; rilrcd.hRILCallRetured = NULL; } } FreeLibrary(hModule); return hr; }

 

该函数实现较为简单，依次调用了RIL_Initialize、RIL_UnregisterFromNetwork和RIL_Deinitialize。由于RIL_UnregisterFromNetwork是异步的，为了等待去附着过程完成就用到了一个Event内核对象，不过这里的WaitForSingleObject函数调用传入的第二个参数是INFINITE，很可能造成主调线程挂起。这个Event内核对象则是通过回调函数RIL_RESULT_Callback在去附着操作完成时设置成signaled状态。

 

PS: 如果微软在实现该函数时给出一个timeout参数就完美了。