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

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[[Category:Symbian C++]][[Category:Code Examples]][[Category:S60 3rd Edition]][[Category:Code Snippet]]
+
{{Archived|timestamp=20120313125306|user=roy.debjit| }}
__NOTOC__
+
[[Category:Symbian C++]][[Category:Code Snippet]][[Category:S60 3rd Edition (initial release)]][[Category:Code Snippet]]
__NOEDITSECTION__
+
{{ArticleMetaData <!-- v1.2 -->
{{KBCS}}
+
{{ArticleMetaData
+
|id=CS000983
+
|platform=S60 3rd Edition, MR
+
|devices=Nokia N95
+
|category=Symbian C++
+
|subcategory=Code Examples
+
|creationdate=May 28, 2008
+
|keywords=CActiveSchedulerWait, CActive, TRequestStatus
+
 
+
 
|sourcecode= <!-- Link to example source code (e.g. [[Media:The Code Example ZIP.zip]]) -->
 
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|sdk=<!-- SDK(s) built and tested against (e.g. [http://linktosdkdownload/ Nokia Qt SDK 1.1]) -->
+
|devices= Nokia N95
|devicecompatability=<!-- Compatible devices (e.g.: All* (must have GPS) ) -->
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|signing=<!-- Empty or one of Self-Signed, DevCert, Manufacturer -->
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|platform= S60 3rd Edition, MR
|capabilities=<!-- Capabilities required (e.g. Location, NetworkServices. -->)
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|author=[[User:Tepaa]]
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|capabilities= <!-- Capabilities required by the article/code example (e.g. Location, NetworkServices. -->
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{{Archived|timestamp=20120313125306|user=roy.debjit| }}
 
 
    
 
    
 
==Overview==
 
==Overview==
Line 35: Line 40:
 
The following capabilities and libraries are required:
 
The following capabilities and libraries are required:
 
<code cpp>
 
<code cpp>
CAPABILITY   None
+
CAPABILITY None
LIBRARY       euser.lib
+
LIBRARY euser.lib
 
</code>
 
</code>
  
Line 69: Line 74:
 
     private:
 
     private:
 
         CSomeAsyncClass*      iSomeAsyncClass;
 
         CSomeAsyncClass*      iSomeAsyncClass;
         CActiveSchedulerWait   iSchedulerWait;
+
         CActiveSchedulerWait iSchedulerWait;
         TInt                   iResult;
+
         TInt iResult;
 
     };
 
     };
 
</code>
 
</code>
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void CMyClass::DoCancel()
 
void CMyClass::DoCancel()
 
     {
 
     {
     // This cancels the DoAsynchronousWithStatusL() method
+
     // This cancels the DoAsynchronousWithStatusL() method
 
     iResult = KErrCancel;
 
     iResult = KErrCancel;
 
     iSchedulerWait.AsyncStop();
 
     iSchedulerWait.AsyncStop();

Revision as of 05:34, 10 May 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: hamishwillee (10 May 2012)

Contents

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 CS000982 - Using CActiveSchedulerWait

MMP file

The following capabilities and libraries are required:

CAPABILITY None
LIBRARY euser.lib

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;
};

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();
}

Postconditions

The asynchronous methods looks like a synchronous method.

See also

CS000982 - Using CActiveSchedulerWait

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