Thread: Scheduling tasks in Windows

I have a script that I wrote in Linux that will read a line from a txt file containing email addresses, and send an email (the body comes from another txt file) to each address on the line that was read. I set up a cron-job so that the script runs on a weekly basis. I have since had numerous requests for the program, but the hitch is that it needs to run on Windows.

I want to write this thing in C, and I am looking for a way to have the program itself set up a schedule and run automatically - this way I can hand the executable to someone (most of the people that are interested in this do not know much at all about using a computer) and they can run it. I will basically have the program be a wizzard that asks questions, and based on the answers set up a scheduled task(s) for Windows to run. Where should I start looking for functions that will let me do that? Thanks.

You can also use the Task Scheduler API. Here is a sample.

Code:

#include <windows.h>
#include <initguid.h>
#include <objbase.h>
#include <mstask.h>
#include <stdio.h>

#if defined(_MSC_VER)
#   pragma comment(lib, "ole32.lib")
#   pragma comment(lib, "advapi32.lib")
#endif

int main(void)
{
  HRESULT         hr            = 0;
  ITaskScheduler* pITS          = NULL;
  ITask*          pITask        = NULL;
  IPersistFile*   pIPersistFile = NULL;
  ITaskTrigger*   pITaskTrigger = NULL;
  TASK_TRIGGER    trigger       = { 0 };
  WORD            newTrigger    = 0;
  BOOL            fSuccess      = FALSE;
  SYSTEMTIME      st            = { 0 };
  WCHAR           szUser[500];
  DWORD           cchUser       = 500;

  CoInitialize(NULL);

  /* Create the task scheduler object. */
  hr = CoCreateInstance(CLSID_CTaskScheduler, NULL, CLSCTX_INPROC_SERVER,
                        IID_ITaskScheduler, (void **) &pITS);
  if (FAILED(hr)) goto cleanup;
 
  /* Create a new work item. */  
  hr = pITS->NewWorkItem(L"Your Task Name",        // Name of task
                         CLSID_CTask,              // Class identifier 
                         IID_ITask,                // Interface identifier
                         (IUnknown**) &pITask);    // Address of task interface
  if (FAILED(hr)) goto cleanup;

  /* Set the application to run (usually should include a path). */
  hr = pITask->SetApplicationName(L"notepad.exe");
  if (FAILED(hr)) goto cleanup;

  /* Only run if the current account is logged on. */
  hr = pITask->SetFlags(TASK_FLAG_RUN_ONLY_IF_LOGGED_ON);
  if (FAILED(hr)) goto cleanup;

  /* Set the user account to use. */
  GetUserNameW(szUser, &cchUser);
  hr = pITask->SetAccountInformation(szUser, NULL);
  if (FAILED(hr)) goto cleanup;

  /* Create trigger (schedule when the task should be triggered). */
  hr = pITask->CreateTrigger(&newTrigger, &pITaskTrigger);
  if (FAILED(hr)) goto cleanup;
  
  /* Define TASK_TRIGGER structure. Note that wBeginDay,
   * wBeginMonth, and wBeginYear must be set to a valid 
   * day, month, and year respectively. */
  GetSystemTime(&st);

  trigger.cbTriggerSize = sizeof (TASK_TRIGGER); 
  trigger.wBeginDay     = st.wDay;          // Start day
  trigger.wBeginMonth   = st.wMonth;        // Start month
  trigger.wBeginYear    = st.wYear;         // Start year
  trigger.wStartHour    = 13;               // 1:00 pm
  trigger.TriggerType   = TASK_TIME_TRIGGER_DAILY;
  trigger.Type.Daily.DaysInterval = 7;      // Days between running
  
  hr = pITaskTrigger->SetTrigger(&trigger);
  if (FAILED(hr)) goto cleanup;

  /* Call IUnknown::QueryInterface to get a pointer to 
   * IPersistFile and IPersistFile::Save to save 
   * the new task to disk. */
  hr = pITask->QueryInterface(IID_IPersistFile, (void **) &pIPersistFile);
  if (FAILED(hr)) goto cleanup;

  hr = pIPersistFile->Save(NULL, TRUE);
  if (FAILED(hr)) goto cleanup;

  fSuccess = TRUE;

cleanup:
  if (pITask)        pITask->Release();
  if (pIPersistFile) pIPersistFile->Release();
  if (pITaskTrigger) pITaskTrigger->Release();
  if (pITS)          pITS->Release();

  if (!fSuccess) fprintf(stderr, "Failed with error code %08x.\n", hr);

  CoUninitialize();
  return 0;
}

I tried this code.
It does not not work for me.
The call of "pITaskTrigger->SetTrigger (&pTrigger)" returns the error 'E_INVALIDARG'

Any ideas ?

I'm using Windows 2003 server, Visual C++ 6