Unicode C

Async Task Chain

See more Async Examples

Demonstrates how to combine a sequence of asynchronous tasks into a single task chain to be run in a background thread. Unicode C

#include <C_CkMailManW.h>
#include <C_CkTaskChainW.h>
#include <C_CkTaskW.h>
#include <C_CkEmailW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkMailManW mailman;
    int numMessages;
    HCkTaskChainW taskChain;
    int i;
    HCkTaskW task;
    HCkEmailW email;
    int numTasks;
    int taskIdx;

    success = FALSE;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    success = FALSE;

    mailman = CkMailManW_Create();

    // Set the POP3 server's hostname
    CkMailManW_putMailHost(mailman,L"pop.example.com");

    // Set the POP3 login/password and any other requirements..
    CkMailManW_putPopUsername(mailman,L"myLogin");
    CkMailManW_putPopPassword(mailman,L"myPassword");
    CkMailManW_putPopSsl(mailman,TRUE);
    CkMailManW_putMailPort(mailman,995);

    // Connect to the POP3 server:
    success = CkMailManW_Pop3BeginSession(mailman);
    if (!success) {
        wprintf(L"%s\n",CkMailManW_lastErrorText(mailman));
        CkMailManW_Dispose(mailman);
        return;
    }

    // Get the number of messages in the mailbox.
    numMessages = CkMailManW_GetMailboxCount(mailman);
    if (numMessages == 0) {
        wprintf(L"No email messages in the POP3 mailbox.\n");
        CkMailManW_Dispose(mailman);
        return;
    }

    taskChain = CkTaskChainW_Create();

    // Create async task objects to fetch each email message
    // by its sequence number

    for (i = 1; i <= numMessages; i++) {

        task = CkMailManW_FetchByMsgnumAsync(mailman,i);
        if (CkMailManW_getLastMethodSuccess(mailman) == FALSE) {
            wprintf(L"%s\n",CkMailManW_lastErrorText(mailman));
            CkMailManW_Dispose(mailman);
            CkTaskChainW_Dispose(taskChain);
            return;
        }

        // Append each task to the task chain.
        success = CkTaskChainW_Append(taskChain,task);
        if (!success) {
            wprintf(L"%s\n",CkTaskChainW_lastErrorText(taskChain));
            CkMailManW_Dispose(mailman);
            CkTaskChainW_Dispose(taskChain);
            return;
        }

        CkTaskW_Dispose(task);

    }

    // At this point, no tasks have actually started running.
    // All we've done so far is to create tasks for the work that will be done
    // when the task chain is run.

    // Start the task chain running in a background thread.
    // Each task is run one after the other (on the same background thread) until all tasks have completed.
    // The task chain will stop at the first task that fails.
    CkTaskChainW_putStopOnFailedTask(taskChain,TRUE);
    success = CkTaskChainW_Run(taskChain);
    if (!success) {
        wprintf(L"%s\n",CkTaskChainW_lastErrorText(taskChain));
        CkMailManW_Dispose(mailman);
        CkTaskChainW_Dispose(taskChain);
        return;
    }

    // The application is now free to do anything else
    // while the emails are being downloaded

    // For this example, we'll simply sleep and periodically
    // check to see if the taskchain if finished. 
    while (CkTaskChainW_getFinished(taskChain) != TRUE) {

        // Sleep 100 ms.
        CkTaskChainW_SleepMs(taskChain,100);

    }

    // A finished task chain could be one that was canceled, aborted, or truly finished.  

    // If the task chain "completed", then it ran to completion.  A "completed" task will
    // have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
    // been aborted or canceled:
    if (CkTaskChainW_getStatusInt(taskChain) != 7) {
        wprintf(L"Task did not complete.\n");
        wprintf(L"task chain status: %s\n",CkTaskChainW_status(taskChain));
        CkMailManW_Dispose(mailman);
        CkTaskChainW_Dispose(taskChain);
        return;
    }

    email = CkEmailW_Create();

    numTasks = CkTaskChainW_getNumTasks(taskChain);
    taskIdx = 0;

    while ((taskIdx < numTasks)) {

        task = CkTaskChainW_GetTask(taskChain,taskIdx);

        // Load the email object with email downloaded by this task.
        success = CkEmailW_LoadTaskResult(email,task);
        if (!success) {
            wprintf(L"Failed to load email object for task.\n");
        }
        else {
            wprintf(L"%s; %s\n",CkEmailW_ck_from(email),CkEmailW_subject(email));
        }

        CkTaskW_Dispose(task);

        taskIdx = taskIdx + 1;
    }



    CkMailManW_Dispose(mailman);
    CkTaskChainW_Dispose(taskChain);
    CkEmailW_Dispose(email);

    }