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C/C++ Code Example: Setting Task Priority

  • Artikkeli

This example sets the priority of a test task and then saves the task. This example assumes that the test task already exists on the local computer.

#include <windows.h>
#include <initguid.h>
#include <ole2.h>
#include <mstask.h>
#include <msterr.h>
#include <wchar.h>


int main(int argc, char **argv)
{
  HRESULT hr = S_OK;
  
  ///////////////////////////////////////////////////////////////////
  // Call CoInitialize to initialize the COM library and then
  // call CoCreateInstance to get the Task Scheduler object.
  ///////////////////////////////////////////////////////////////////
  ITaskScheduler *pITS;
  
  hr = CoInitialize(NULL);
  if (SUCCEEDED(hr))
  {
    hr = CoCreateInstance(CLSID_CTaskScheduler,
                          NULL,
                          CLSCTX_INPROC_SERVER,
                          IID_ITaskScheduler,
                          (void **) &pITS);
    if (FAILED(hr))
    {
      CoUninitialize();
      return 1;
    }
  }
  else
  {
    return 1;
  }
  
  
  ///////////////////////////////////////////////////////////////////
  // Call ITaskScheduler::Activate to get the Task object.
  ///////////////////////////////////////////////////////////////////
  ITask *pITask;
  LPCWSTR lpcwszTaskName;
  lpcwszTaskName = L"Test Task";
  hr = pITS->Activate(lpcwszTaskName,
                      IID_ITask,
                     (IUnknown**) &pITask);
  
  // Release the ITaskScheduler interface.
  pITS->Release();  
  
  if (FAILED(hr))
  {
    wprintf(L"Failed calling ITaskScheduler::Activate: ");
    wprintf(L"error = 0x%x\n",hr);
    CoUninitialize();
    return 1;
  }
  
  
  ///////////////////////////////////////////////////////////////////
  // Call ITask::SetPriority to specify the priority level of 
  // Test Task.
  ///////////////////////////////////////////////////////////////////
  DWORD dwPriority = HIGH_PRIORITY_CLASS;
  
  hr = pITask->SetPriority(dwPriority);
  
  if (FAILED(hr))
  {
    wprintf(L"Failed calling ITask::SetPriority: ");
    wprintf(L"error = 0x%x\n",hr);
    pITask->Release();
    CoUninitialize();
    return 1;
  }
  
  
  ///////////////////////////////////////////////////////////////////
  // Call IPersistFile::Save to save the modified task to disk.
  ///////////////////////////////////////////////////////////////////
  IPersistFile *pIPersistFile;
  
  hr = pITask->QueryInterface(IID_IPersistFile,
                              (void **)&pIPersistFile);
  
  // Release the ITask interface.
  pITask->Release();  
  
  hr = pIPersistFile->Save(NULL,
                           TRUE);
  
  if (FAILED(hr))
  {
    wprintf(L"Failed calling IPersistFile::Save: ");
    wprintf(L"error = 0x%x\n",hr);
    pIPersistFile->Release();
    CoUninitialize();
    return 1;
  }

  // Release the IPersistFile interface.
  pIPersistFile->Release();
  
  wprintf(L"Set the priority of TestTask to HIGH_PRIORITY_CLASS.\n");
  
  CoUninitialize();
  return 0;
}

Task Scheduler 1.0 Examples