Reading Unread POP3 Email

The POP3 protocol does not provide the ability to ask the server which emails are "unread". Furthermore, a pure POP3 server does not even keep this information. Some servers, such as Exchange Server, expose both POP3 and IMAP interfaces. In these cases, information about read/unread status exists on the server, but it is only available via the IMAP protocol. Email clients such as Outlook and Thunderbird keep read/unread information on the client computer. This example demonstrates how UIDLs can be saved to track and read "unread" email.

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#include <CkMailMan.h>
#include <CkStringArray.h>
#include <CkEmailBundle.h>
#include <CkEmail.h>

void ChilkatSample(void)
    {
    //  The mailman object is used for receiving (POP3)
    //  and sending (SMTP) email.
    CkMailMan mailman;

    //  Any string argument automatically begins the 30-day trial.
    bool success;
    success = mailman.UnlockComponent("30-day trial");
    if (success != true) {
        printf("Component unlock failed\n");
        return;
    }

    //  Set the POP3 server's hostname
    mailman.put_MailHost("mail.chilkatsoft.com");

    //  Set the POP3 login/password.
    mailman.put_PopUsername("***");
    mailman.put_PopPassword("***");

    //  You may keep a list of already-seen UIDLs in a text file:
    //  If this is the first time you're running this example,
    //  create an empty text file named "seenUidls.txt"
    CkStringArray saSeenUidls;
    success = saSeenUidls.LoadFromFile("seenUidls.txt");
    if (success != true) {
        printf("failed to load seenUidls.txt\n");
        return;
    }

    //  Get the complete list of UIDLs on the mail server.
    CkStringArray *saUidls = 0;
    saUidls = mailman.GetUidls();

    if (saUidls == 0 ) {
        printf("%s\n",mailman.lastErrorText());
        return;
    }

    //  Create a new string array object (it's an object, not an actual array)
    //  and add the UIDLs from saUidls that aren't already seen.
    CkStringArray saUnseenUidls;

    long i;
    long n;
    n = saUidls->get_Count();
    for (i = 0; i <= n - 1; i++) {
        if (saSeenUidls.Contains(saUidls->getString(i)) != true) {
            saUnseenUidls.Append(saUidls->getString(i));
        }

    }

    if (saUnseenUidls.get_Count() == 0) {
        printf("No unseen emails!\n");
        delete saUidls;
        return;
    }

    //  Download in full the unseen emails:
    CkEmailBundle *bundle = 0;

    bundle = mailman.FetchMultiple(saUnseenUidls);
    if (bundle == 0 ) {
        printf("%s\n",mailman.lastErrorText());
        delete saUidls;
        return;
    }

    CkEmail *email = 0;
    for (i = 0; i <= bundle->get_MessageCount() - 1; i++) {
        email = bundle->GetEmail(i);
        printf("%s\n",email->ck_from());
        printf("%s\n",email->subject());
        printf("----\n");
        delete email;
    }

    //  Save saUidls to "seenUidls.txt"
    saUidls->SaveToFile("seenUidls.txt");

    delete saUidls;
    }