(MFC) Thread Pool Size

Demonstrates how to set the maximum number of threads in Chilkat's thread pool manager. Also demonstrates how to set a thread pool log file for help in diagnosing unexpected problems.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkGlobal.h>
#include <CkHttp.h>
#include <CkTask.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // All Chilkat classes can be unlocked at once at the beginning of a program
    // by calling UnlockBundle.  It requires a Bundle unlock code.
    CkGlobal chilkatGlob;
    bool success = chilkatGlob.UnlockBundle("Anything for 30-day trial.");
    if (success != true) {
        strOut.append(chilkatGlob.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Set the maximum number of threads in the Chilkat thread pool to 12.
    // This means that no more than 12 background worker threads will exist simultaneously.
    // If more than 12 tasks are queued then some must wait for a worker thread to become free.
    // Note: The Chilkat thread pool manager thread is a thread distinct from the
    // worker threads.  It starts when the 1st asynchronous task is Run. 
    chilkatGlob.put_MaxThreads(12);

    // Also, the ThreadPoolLogPath can be set to cause the thread pool manager thread to
    // keep a log file. This is for the purpose of debugging if unexpected problems occur.
    chilkatGlob.put_ThreadPoolLogPath("/home/users/chilkat/logs/threadPoolLog.txt");

    CkHttp http1;
    CkHttp http2;
    CkHttp http3;

    const char *url1 = "http://www.marcusmiller.com/";
    const char *url2 = "http://www.tromboneshorty.com/";
    const char *url3 = "http://www.jamesmorrison.com/";

    // Call the async version of the QuickGetStr method to return a task object.
    // The task object is loaded, but is in the Inert state -- meaning it is
    // not yet scheduled to run on Chilkat's background thread pool.
    CkTask *task1 = http1.QuickGetStrAsync(url1);
    if (http1.get_LastMethodSuccess() == false) {
        strOut.append(http1.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkTask *task2 = http2.QuickGetStrAsync(url2);
    if (http2.get_LastMethodSuccess() == false) {
        strOut.append(http2.lastErrorText());
        strOut.append("\r\n");
        delete task1;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkTask *task3 = http3.QuickGetStrAsync(url3);
    if (http3.get_LastMethodSuccess() == false) {
        strOut.append(http3.lastErrorText());
        strOut.append("\r\n");
        delete task1;
        delete task2;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // At this point we have 3 task objects, each loaded with a Chilkat method call.
    // Note: At this point no background threads are running.  The thread pool manager
    // thread is not started -- it will start when the very first task is Run.

    // Schedule each task for running on the thread pool.  This changes each task's state
    // from Inert to Live. The thread pool manager thread starts with the 1st task queued.
    // If the Global.ThreadPoolLogPath property was set, then
    // the log file would be created (or appended) at this point.
    success = task1->Run();
    // Assuming success for brevity...
    success = task2->Run();
    success = task3->Run();

    // The application is now free to do anything else
    // while the HTML at the URL's are being downloaded in background threads.

    // In this case, we'll just wait for all three tasks to finish.
    // All three tasks are running simultaneously in separate background threads.
    // We can wait for each in any order.  If Wait is called and the task has already
    // finished (or been canceled), then the Wait method returns immediately.
    int maxWaitMs = 20000;
    success = task1->Wait(maxWaitMs);
    success = task2->Wait(maxWaitMs);
    success = task3->Wait(maxWaitMs);
    // Assuming success for brevity...

    const char *err = "Task failed or canceled";
    const char *html1 = err;
    const char *html2 = err;
    const char *html3 = err;

    // Now get the HTML downloaded in each task:
    if ((task1->get_StatusInt() == 7) && (task1->get_TaskSuccess() == true)) {
        html1 = task1->getResultString();
    }

    if ((task2->get_StatusInt() == 7) && (task2->get_TaskSuccess() == true)) {
        html2 = task2->getResultString();
    }

    if ((task3->get_StatusInt() == 7) && (task3->get_TaskSuccess() == true)) {
        html3 = task3->getResultString();
    }

    strOut.append(html1);
    strOut.append("\r\n");
    strOut.append("----");
    strOut.append("\r\n");
    strOut.append(html2);
    strOut.append("\r\n");
    strOut.append("----");
    strOut.append("\r\n");
    strOut.append(html3);
    strOut.append("\r\n");
    strOut.append("----");
    strOut.append("\r\n");

    delete task1;
    delete task2;
    delete task3;


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }