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Archived:Changing asynchronous method to synchronous in Symbian C++

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{{Archived|timestamp=20120313125306|user=roy.debjit| }}
 
 
[[Category:Symbian C++]][[Category:Code Snippet]][[Category:S60 3rd Edition (initial release)]][[Category:Code Snippet]]
 
[[Category:Symbian C++]][[Category:Code Snippet]][[Category:S60 3rd Edition (initial release)]][[Category:Code Snippet]]
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{{Archived|timestamp=20120313125306|user=roy.debjit| }}
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{{ArticleMetaData <!-- v1.2 -->
 
{{ArticleMetaData <!-- v1.2 -->
 
|sourcecode= <!-- Link to example source code (e.g. [[Media:The Code Example ZIP.zip]]) -->
 
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==Overview==
 
==Overview==
This code snippet shows how to change an asynchronous method interface to a  
+
{{Abstract|This code snippet shows how to change an asynchronous method interface to a synchronous method. This can be done with CActiveSchedulerWait.}}
synchronous method. This can be done with CActiveSchedulerWait.
+
  
 
There are two different synchronous methods:
 
There are two different synchronous methods:
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* CMyClass::DoAsynchronousWithStatusL() uses CActiveSchedulerWait for waiting for the asynchronous method that has TRequestStatus in its interface. The method completes with CMyClass::RunL().
 
* CMyClass::DoAsynchronousWithStatusL() uses CActiveSchedulerWait for waiting for the asynchronous method that has TRequestStatus in its interface. The method completes with CMyClass::RunL().
  
For more information on using CActiveSchedulerWait, see article  [[Using CActiveSchedulerWait]]
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For more information on using CActiveSchedulerWait, see article  [[Archived:Using CActiveSchedulerWait]]
  
 
==MMP file==
 
==MMP file==
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==See also==
 
==See also==
[[Using CActiveSchedulerWait]]
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[[Archived:Using CActiveSchedulerWait]]

Latest revision as of 01:26, 25 August 2012

Archived.pngArchived: This article is archived because it is not considered relevant for third-party developers creating commercial solutions today. If you think this article is still relevant, let us know by adding the template {{ReviewForRemovalFromArchive|user=~~~~|write your reason here}}.

Article Metadata
Tested with
Devices(s): Nokia N95
Compatibility
Platform(s): S60 3rd Edition, MR
S60 3rd Edition (initial release)
Article
Keywords: CActiveSchedulerWait, CActive, TRequestStatus
Created: tepaa (21 May 2008)
Last edited: lpvalente (25 Aug 2012)

Contents

[edit] Overview

This code snippet shows how to change an asynchronous method interface to a synchronous method. This can be done with CActiveSchedulerWait.

There are two different synchronous methods:

  • CMyClass::DoAsynchronousL() uses CActiveSchedulerWait for waiting for the asynchronous method that completes with CMyClass::AsyncComplete()
  • CMyClass::DoAsynchronousWithStatusL() uses CActiveSchedulerWait for waiting for the asynchronous method that has TRequestStatus in its interface. The method completes with CMyClass::RunL().

For more information on using CActiveSchedulerWait, see article Archived:Using CActiveSchedulerWait

[edit] MMP file

The following capabilities and libraries are required:

CAPABILITY None
LIBRARY euser.lib

[edit] Header

#include <e32base.h>
 
// for CSomeAsyncClass
class MAsynchIF
{
public:
void AsyncComplete(TInt aResult);
};
 
class CMyClass : public CActive, MAsynchIF
{
public:
static CMyClass* NewLC();
virtual ~CMyClass();
 
// Synchronous methods
TInt DoAsynchronousL();
TInt DoAsynchronousWithStatusL();
 
private: // From MAsynchIF (CSomeAsyncClass)
void AsyncComplete(TInt aResult);
 
private: // From CActive
void RunL();
void DoCancel();
 
private:
CSomeAsyncClass* iSomeAsyncClass;
CActiveSchedulerWait iSchedulerWait;
TInt iResult;
};

[edit] Source

CMyClass* CMyClass::NewLC()
{
CMyClass* self = new (ELeave) CMyClass();
CleanupStack::PushL(self);
self->ConstructL();
return self;
}
 
CMyClass::CMyClass()
: CActive(CActive::EPriorityStandard)
{
}
 
void CMyClass::ConstructL()
{
CActiveScheduler::Add(this);
iSomeAsyncClass = CSomeAsyncClass::NewL(this);
}
 
CMyClass::~CMyClass()
{
Cancel();
delete iSomeAsyncClass;
}
 
// This is a synchronous method even though it calls an asynchronous interface that
// completes with CMyClass::AsyncComplete()
TInt CMyClass::DoAsynchronousL()
{
User::LeaveIfError(iSomeAsyncClass->SomeAsynchronousIfL());
 
iSchedulerWait.Start();
// Continues here after CMyClass::AsyncComplete() is called
// by CSomeAsyncClass.
 
return iResult;
}
 
void CMyClass::AsyncComplete(TInt aResult)
{
iResult = aResult;
iSchedulerWait.AsyncStop();
}
 
// This is an synchronous method even though it calls an asynchronous interface that
// completes with CMyClass::RunL() because it uses TRequestStatus as
// a parameter
TInt CMyClass::DoAsynchronousWithStatusL()
{
if (!IsActive())
{
User::LeaveIfError(iSomeAsyncClass->SomeAsynchronousIfL(iStatus));
SetActive();
 
iSchedulerWait.Start();
// Continues here after CMyClass::RunL() is called
// by CSomeAsyncClass.
}
else
{
User::Leave(KErrNotReady);
}
return iResult;
}
 
void CMyClass::RunL()
{
// This is called when DoAsynchronousWithStatusL() completes
iResult = iStatus.Int();
iSchedulerWait.AsyncStop();
}
 
void CMyClass::DoCancel()
{
// This cancels the DoAsynchronousWithStatusL() method
iResult = KErrCancel;
iSchedulerWait.AsyncStop();
}

[edit] Postconditions

The asynchronous methods looks like a synchronous method.

[edit] See also

Archived:Using CActiveSchedulerWait

This page was last modified on 25 August 2012, at 01:26.
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