Xojo Plugin

Thread Pool Size

See more Async Examples

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. Xojo Plugin

Dim success As Boolean
success = False

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

success = False

// 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. 
Dim glob As New Chilkat.CkGlobal
glob.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.
glob.ThreadPoolLogPath = "/home/users/chilkat/logs/threadPoolLog.txt"

Dim http1 As New Chilkat.Http
Dim http2 As New Chilkat.Http
Dim http3 As New Chilkat.Http

Dim url1 As String
url1 = "http://www.marcusmiller.com/"
Dim url2 As String
url2 = "http://www.tromboneshorty.com/"
Dim url3 As String
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.
Dim task1 As Chilkat.Task
task1 = http1.QuickGetStrAsync(url1)
If (http1.LastMethodSuccess = False) Then
    System.DebugLog(http1.LastErrorText)
    Return
End If

Dim task2 As Chilkat.Task
task2 = http2.QuickGetStrAsync(url2)
If (http2.LastMethodSuccess = False) Then
    System.DebugLog(http2.LastErrorText)

    Return
End If

Dim task3 As Chilkat.Task
task3 = http3.QuickGetStrAsync(url3)
If (http3.LastMethodSuccess = False) Then
    System.DebugLog(http3.LastErrorText)

    Return
End If

// 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.
Dim maxWaitMs As Int32
maxWaitMs = 20000
success = task1.Wait(maxWaitMs)
success = task2.Wait(maxWaitMs)
success = task3.Wait(maxWaitMs)
// Assuming success for brevity...

Dim err As String
err = "Task failed or canceled"
Dim html1 As String
html1 = err
Dim html2 As String
html2 = err
Dim html3 As String
html3 = err

// Now get the HTML downloaded in each task:
If ((task1.StatusInt = 7) And (task1.TaskSuccess = True)) Then
    html1 = task1.GetResultString()
End If

If ((task2.StatusInt = 7) And (task2.TaskSuccess = True)) Then
    html2 = task2.GetResultString()
End If

If ((task3.StatusInt = 7) And (task3.TaskSuccess = True)) Then
    html3 = task3.GetResultString()
End If

System.DebugLog(html1)
System.DebugLog("----")
System.DebugLog(html2)
System.DebugLog("----")
System.DebugLog(html3)
System.DebugLog("----")