Visual FoxPro

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. Visual FoxPro

LOCAL lnSuccess
LOCAL loGlob
LOCAL loHttp1
LOCAL loHttp2
LOCAL loHttp3
LOCAL lcUrl1
LOCAL lcUrl2
LOCAL lcUrl3
LOCAL loTask1
LOCAL loTask2
LOCAL loTask3
LOCAL lnMaxWaitMs
LOCAL lcErr
LOCAL lcHtml1
LOCAL lcHtml2
LOCAL lcHtml3

lnSuccess = 0

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

lnSuccess = 0

* 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. 
loGlob = CreateObject('Chilkat.Global')
loGlob.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.
loGlob.ThreadPoolLogPath = "/home/users/chilkat/logs/threadPoolLog.txt"

loHttp1 = CreateObject('Chilkat.Http')
loHttp2 = CreateObject('Chilkat.Http')
loHttp3 = CreateObject('Chilkat.Http')

lcUrl1 = "http://www.marcusmiller.com/"
lcUrl2 = "http://www.tromboneshorty.com/"
lcUrl3 = "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.
loTask1 = loHttp1.QuickGetStrAsync(lcUrl1)
IF (loHttp1.LastMethodSuccess = 0) THEN
    ? loHttp1.LastErrorText
    RELEASE loGlob
    RELEASE loHttp1
    RELEASE loHttp2
    RELEASE loHttp3
    CANCEL
ENDIF

loTask2 = loHttp2.QuickGetStrAsync(lcUrl2)
IF (loHttp2.LastMethodSuccess = 0) THEN
    ? loHttp2.LastErrorText
    RELEASE loTask1
    RELEASE loGlob
    RELEASE loHttp1
    RELEASE loHttp2
    RELEASE loHttp3
    CANCEL
ENDIF

loTask3 = loHttp3.QuickGetStrAsync(lcUrl3)
IF (loHttp3.LastMethodSuccess = 0) THEN
    ? loHttp3.LastErrorText
    RELEASE loTask1
    RELEASE loTask2
    RELEASE loGlob
    RELEASE loHttp1
    RELEASE loHttp2
    RELEASE loHttp3
    CANCEL
ENDIF

* 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.
lnSuccess = loTask1.Run()
* Assuming success for brevity...
lnSuccess = loTask2.Run()
lnSuccess = loTask3.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.
lnMaxWaitMs = 20000
lnSuccess = loTask1.Wait(lnMaxWaitMs)
lnSuccess = loTask2.Wait(lnMaxWaitMs)
lnSuccess = loTask3.Wait(lnMaxWaitMs)
* Assuming success for brevity...

lcErr = "Task failed or canceled"
lcHtml1 = lcErr
lcHtml2 = lcErr
lcHtml3 = lcErr

* Now get the HTML downloaded in each task:
IF ((loTask1.StatusInt = 7) AND (loTask1.TaskSuccess = 1)) THEN
    lcHtml1 = loTask1.GetResultString()
ENDIF

IF ((loTask2.StatusInt = 7) AND (loTask2.TaskSuccess = 1)) THEN
    lcHtml2 = loTask2.GetResultString()
ENDIF

IF ((loTask3.StatusInt = 7) AND (loTask3.TaskSuccess = 1)) THEN
    lcHtml3 = loTask3.GetResultString()
ENDIF

? lcHtml1
? "----"
? lcHtml2
? "----"
? lcHtml3
? "----"

RELEASE loTask1
RELEASE loTask2
RELEASE loTask3

RELEASE loGlob
RELEASE loHttp1
RELEASE loHttp2
RELEASE loHttp3