(C) Async Methods Returning an Object

Demonstrates how to call an asynchronous method that returns an object. This example reads email from a POP3 server using the Async versions of the Chilkat methods.

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#include <C_CkGlobal.h>
#include <C_CkMailMan.h>
#include <C_CkTask.h>
#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    HCkGlobal chilkatGlob;
    BOOL success;
    HCkMailMan mailman;
    HCkTask task;
    int maxWaitMs;
    int numMessages;
    HCkEmail email;
    int i;

    // All Chilkat classes can be unlocked at once at the beginning of a program
    // by calling UnlockBundle.  It requires a Bundle unlock code.
    chilkatGlob = CkGlobal_Create();
    success = CkGlobal_UnlockBundle(chilkatGlob,"Anything for 30-day trial.");
    if (success != TRUE) {
        printf("%s\n",CkGlobal_lastErrorText(chilkatGlob));
        CkGlobal_Dispose(chilkatGlob);
        return;
    }

    mailman = CkMailMan_Create();

    // Set the POP3 server's hostname
    CkMailMan_putMailHost(mailman,"pop.someMailServer.com");

    // Set the POP3 login/password and any other requirements..
    CkMailMan_putPopUsername(mailman,"myLogin");
    CkMailMan_putPopPassword(mailman,"myPassword");
    CkMailMan_putPopSsl(mailman,TRUE);
    CkMailMan_putMailPort(mailman,995);

    // Connect to the POP3 server:
    task = CkMailMan_Pop3BeginSessionAsync(mailman);
    if (CkMailMan_getLastMethodSuccess(mailman) == FALSE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkGlobal_Dispose(chilkatGlob);
        CkMailMan_Dispose(mailman);
        return;
    }

    // Start the background task.
    success = CkTask_Run(task);
    if (!success) {
        printf("%s\n",CkTask_lastErrorText(task));
        CkTask_Dispose(task);
        CkGlobal_Dispose(chilkatGlob);
        CkMailMan_Dispose(mailman);
        return;
    }

    // Wait for the POP3 connect task to finish.
    // The TRUE/FALSE returned by Wait applies to the Wait method call, not the task.
    maxWaitMs = 30000;
    success = CkTask_Wait(task,maxWaitMs);
    if (!success || (CkTask_getStatusInt(task) != 7) || (CkTask_getTaskSuccess(task) != TRUE)) {
        if (!success) {
            // The task.LastErrorText applies to the Wait method call.
            printf("%s\n",CkTask_lastErrorText(task));
        }
        else {
            // The ResultErrorText applies to the underlying task method call (i.e. the Pop3BeginSession)
            printf("%s\n",CkTask_status(task));
            printf("%s\n",CkTask_resultErrorText(task));
        }

        CkTask_Dispose(task);
        CkGlobal_Dispose(chilkatGlob);
        CkMailMan_Dispose(mailman);
        return;
    }

    CkTask_Dispose(task);

    // Get the number of messages in the mailbox.
    task = CkMailMan_GetMailboxCountAsync(mailman);

    // To keep the example short, we'll skip handling failures.
    // The failures would be handled in the same way as shown above.

    success = CkTask_Run(task);
    success = CkTask_Wait(task,maxWaitMs);
    numMessages = CkTask_GetResultInt(task);
    CkTask_Dispose(task);
    if (numMessages == 0) {
        CkGlobal_Dispose(chilkatGlob);
        CkMailMan_Dispose(mailman);
        return;
    }

    email = CkEmail_Create();

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

        task = CkMailMan_FetchByMsgnumAsync(mailman,i);
        if (CkMailMan_getLastMethodSuccess(mailman) == FALSE) {
            printf("%s\n",CkMailMan_lastErrorText(mailman));
            CkGlobal_Dispose(chilkatGlob);
            CkMailMan_Dispose(mailman);
            CkEmail_Dispose(email);
            return;
        }

        success = CkTask_Run(task);
        success = CkTask_Wait(task,maxWaitMs);
        if (!success || (CkTask_getStatusInt(task) != 7) || (CkTask_getTaskSuccess(task) != TRUE)) {
            if (!success) {
                // The task.LastErrorText applies to the Wait method call.
                printf("%s\n",CkTask_lastErrorText(task));
            }
            else {
                // The ResultErrorText applies to the underlying task method call (i.e. the FetchByMsgnum)
                printf("%s\n",CkTask_status(task));
                printf("%s\n",CkTask_resultErrorText(task));
            }

            CkTask_Dispose(task);
            CkGlobal_Dispose(chilkatGlob);
            CkMailMan_Dispose(mailman);
            CkEmail_Dispose(email);
            return;
        }

        // Each Chilkat object that can be a return value of an asynchronous task will
        // have a method named LoadTaskResult.  The object returned in the underlying
        // asynchronous method call is retrieved by calling LoadTaskResult. 

        // To say it another way: The application will provide a pre-existing object of
        // the desired return type (in this case it is an email object).  This object is
        // loaded by calling LoadTaskResult.  

        success = CkEmail_LoadTaskResult(email,task);
        CkTask_Dispose(task);

        if (!success) {
            printf("%s\n",CkEmail_lastErrorText(email));
            CkGlobal_Dispose(chilkatGlob);
            CkMailMan_Dispose(mailman);
            CkEmail_Dispose(email);
            return;
        }
        else {
            printf("%s: %s\n\n",CkEmail_ck_from(email),CkEmail_subject(email));
        }

    }



    CkGlobal_Dispose(chilkatGlob);
    CkMailMan_Dispose(mailman);
    CkEmail_Dispose(email);

    }