Asynchronous services example codes

These files are found in: examples\Base\IPC\Async\SingleRequest

The files reproduced here are the main files contained in the examples directory. Some extra files may be needed to run the examples, and these will be found in the appropriate examples directory.

// SingleRequest.cpp
//
// Copyright (C) Symbian Software Ltd 2000-2005.  All rights reserved.
//
//  Shows asynchronous programming (without active objects).
//  Example shows how a single request can be issued, followed
//  by User::WaitForRequest()


#include "CommonFramework.h"



// Do the example
LOCAL_C void doExampleL()
    {
      // create and initialize heartbeat timer
    RTimer heartbeat;               // heartbeat timer

    TRequestStatus heartbeatStatus; // request status associated with it
    heartbeat.CreateLocal();        // always created for this thread

      // go round timing loop
    for (TInt i=0; i<10; i++)
        {
          // issue and wait for single request
        heartbeat.After(heartbeatStatus,1000000); // wait 1 second
        User::WaitForRequest(heartbeatStatus);    // wait for request
                                                  // to complete
          // say we're here
        _LIT(KFormatString1,"Tick %d\n");
        console->Printf(KFormatString1, i);
        }

      // close timer
    heartbeat.Close(); // close timer
    }

This file is found in examples\Base\CommonFramework

// EUSTD.H
//
// Copyright (C) Symbian Software Ltd 1997-2005.  All rights reserved.
//

#ifndef __EUSTD_H
#define __EUSTD_H

#include <e32base.h>
#include <e32cons.h>

_LIT(KTxtEPOC32EX,"EPOC32EX");
_LIT(KTxtExampleCode,"E32 SDK Example Code");
_LIT(KFormatFailed,"failed: leave code=%d");
_LIT(KTxtOK,"ok");
_LIT(KTxtPressAnyKey," [press any key]");

// public
LOCAL_D CConsoleBase* console; // write all your messages to this
LOCAL_C void doExampleL(); // code this function for the real example

// private
LOCAL_C void callExampleL(); // initialize with cleanup stack, then do example

GLDEF_C TInt E32Main() // main function called by E32
    {
    __UHEAP_MARK;
    CTrapCleanup* cleanup=CTrapCleanup::New(); // get clean-up stack
    TRAPD(error,callExampleL()); // more initialization, then do example
    __ASSERT_ALWAYS(!error,User::Panic(KTxtEPOC32EX,error));
    delete cleanup; // destroy clean-up stack
    __UHEAP_MARKEND;
    return 0; // and return
    }

LOCAL_C void callExampleL() // initialize and call example code under cleanup stack
    {
    console=Console::NewL(KTxtExampleCode,TSize(KConsFullScreen,KConsFullScreen));
    CleanupStack::PushL(console);
    TRAPD(error,doExampleL()); // perform example function
    if (error)
        console->Printf(KFormatFailed, error);
    else
        console->Printf(KTxtOK);
    console->Printf(KTxtPressAnyKey);
    console->Getch(); // get and ignore character
    CleanupStack::PopAndDestroy(); // close console
    }

#endif

// BLD.INF
// Component description file 

// Copyright (C) Symbian Software Ltd 2000-2005.  All rights reserved.

PRJ_MMPFILES

SingleRequest.mmp

// SingleRequest.mmp
//
// Copyright (C) Symbian Software Ltd 2000-2005.  All rights reserved.

// using relative paths for source and userinclude directories

// No explicit capabilities required to run this.

TARGET        SingleRequest.exe
TARGETTYPE    exe
UID           0
VENDORID 0x70000001

SOURCEPATH    .
SOURCE        SingleRequest.cpp

USERINCLUDE   .
USERINCLUDE   ..\..\..\CommonFramework
SYSTEMINCLUDE \Epoc32\include

LIBRARY       euser.lib

CAPABILITY    None

This example shows how to issue and wait for a single request.

The example shows the general principles involved in asynchronous programming. It uses a simple wait loop and shows how the completion of asynchronous events are handled without active objects.

This example deliberately does not use active objects.

• TRequestStatus: Asynchronous request status

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.

Found in: examples\Base\IPC\Async\WaitLoop

This example shows how a wait loop can be used to identify and handle a completed request.

It shows the general principles involved in asynchronous programming. It uses a simple wait loop and shows how the completion of asynchronous events are handled without active objects.

This example deliberately does not use active objects.

• TRequestStatus: asynchronous request status

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.

Found in: examples\Base\IPC\Async\RealLifeWaitLoop

As with the WaitLoop example, this example shows how a wait loop can be used to identify and handle a completed request. However, this example shows how the wait loop can deal with multiple asynchronous service providers.

The example shows the general principles involved in asynchronous programming; it uses a simple wait loop and shows how the completion of asynchronous events are handled without active objects.

This example deliberately does not use active objects.

• TRequestStatus: asynchronous request status

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.

Found in: examples\Base\IPC\Async\RunComplete

The example shows how active objects and an active scheduler can be used to handle asynchronous events. Compare this with the following examples; SingleRequest, WaitLoop and RealLifeWaitLoop.

It demonstrates a single CMessageTimer active object which runs until completion.

• TRequestStatus: asynchronous request status

• CActiveScheduler: the active scheduler

• CActive: active object abstraction

• CTimer: timer base class (used here as a source of events)

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.

Found in: examples\Base\IPC\Async\AcceptInputX

These examples show how active objects and an active scheduler can be used to handle asynchronous events.

They demonstrate a single CKeyMessengerProcessor active object (derived from class CActiveConsole), which accepts input from keyboard, but does not print it. This object contains a CMessageTimer object which it activates if the user inputs the character "m" and cancelled if the user inputs "c".

• TRequestStatus: asynchronous request status

• CActiveScheduler: the active scheduler

• CActive: active object abstraction

• CTimer: timer base class (used here as a source of events)

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.

Found in: examples\Base\IPC\Async\FibonacciX

These examples show how active objects and an active scheduler can be used to handle asynchronous events and long-running services to maintain system responsiveness.

• TRequestStatus: asynchronous request status

• CActiveScheduler: the active scheduler

• CActive: active object abstraction

• CTimer: timer base class (used here as a source of events)

The example requires no specific capabilities in order to run - and does not demonstrate any security issues.