Reading Network Paramters in 3rd edition -Synchronously

Comments

is this example correct?

I tried it and it works, but I figure this is by accident. Let me explain :

GetNetworkParameters() makes a CNetworkApp() instance, then Contructs()s it then Destroys it.

Construct() starts the scheduler which then calls RunL() when the info is ready. However, since RunL() is run asynchronously to GetNetworkParameters(), the CNetworkApp() instance could already have been Destroyed before RunL() is called. I think it's only by chance that RunL() completes before GetNetworkParemeters() has Destroyed it.

What do you think?

Response:

The key is the call to CActiveScheduler::Start(). This starts off a new wait loop in the scheduler, and Start() will not return until a matching call to CActiveScheduler::Stop().

davidmaxwaterman 07:24, 30 May 2007 (UTC)

Hi,

I have tried this and it works but only to a point. If for example you were to do this:

case ECommand2: { TUint CellId;

       TBuf<30> NetworkId;
       TBuf<30> CountryId;
       TBuf<30> OperatorLongName;        
       
       for(test_length = 0; test_length < 1000; test_length++)
       {
CNetworkApp::GetNetworkParameters(CellId,NetworkId,CountryId,OperatorLongName);
       User::After(1000000);
       }
        
       TBuf<160> iDisplayString;
       iDisplayString.Format(
               _L( "CellId-%d\nNetworkID-%S\nCountryID-%S\nNETWORK-%S" ),
                CellId, &NetworkId, &CountryId, &OperatorLongName );

       CAknInformationNote* informationNote = new ( ELeave )
               CAknInformationNote;
       informationNote->ExecuteLD(iDisplayString);

}

The program will run out of memory after a few minutes (around 3 minutes). Now I know that a person will not be refreshing this information as quickly as the above code but it still leaves a problem where, after the user has refreshed >200 times the program will crash and will need to be restarted.

Regards, Seamus

Memory Leaking Issue

Very useful example, but have some problems on it.Appreciated if someone can give hints on it.

I encounter the sample problem as Seamus, after try to get Call CNetworkApp::GetNetworkParameters around 200 times, i got the out of memory error.

Seamus, is there any updates on this issue?

And i got another issue, sometimes i get the cell id value "0" with the above method, but the rest of informations(network provider,country code..) are all correct.Anyone have ideal on this?

I also have a question on the sample code given. In the ConstructL, the line CActiveScheduler::Add(this); will add active object itself to the current ActiveScheduler. As every call to CNetworkApp::GetNetworkParameters will create a new instance of CNetworkApp, thus a new reference will be added to ActiveScheduler, i never see the reference was removed from ActiveScheduler. I think we should call Deque() in the method RunL() to remove the current active object from Scheduler.

caowei

Memory Leaking Issue

Hi caowei,

I have been working on this but as yet, i have not managed to fix the problem. You are correct in saying that objects are being added and not removed correctly as I have tracked the memory usage on my N91 as I run the program and memory is constantly being eaten up until the memory full error message.

And I suspect you are correct that it is to do with the active scheduler but i am not fully up on the ins and outs of the Active scheduler so im still trying to find the solution.

May i suggest that both of us work together to fix the problem?

On your cell Id problem, I have a problem where I get the incorrect value a lot of the time and I have found out that There is an extra value for the hex value of the cell id and I had to code in a check to make sure it only used the 4 least significant bits to calculate the true cell id all of the time.

newCellId_1 = CellId & 0xFFFF;

Seamus

Memory Leaking Issue and Cell ID Issue

Hi Seamus

Thanks for your reply.

The Memory leaking issue has been resolved already,the issue is because we didn't clean up the pointer "CTelephony* iTelephony" in the sample code. After i added a de-constructor i didn't encounter memory full issue anymore.

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CNetworkApp::~CNetworkApp() { if(iTelephony) { iTelephony->CancelEstablishDataCall(); iTelephony->CancelReceiveDataCall(); delete iTelephony; iTelephony = NULL; } }

---

For the cell id issue, could you explain more on the problem you encountered before? My issue only happens while i'm using 3G network, everytime i can get the correct CELL ID when i'm using GSM netwrok. You mentioned that you find the special bit for the Hex cell id value, could you suggest how to display the this original Hex format value? Is is possible to return CELL ID's original format without format using "d%"?

As most of times i still can get the correct cell id, now my interim solution is to warp the original method "CNetworkApp::GetNetworkParameters", write a loop , if i get the cell id "0", i invoke the GetNetworkParameters again until i get the correct cell id.

I suspect this is a Symbian bug, any hints on this?

BTW, i'm contable at cn.caowei@gmail.com for further discussion. I'm knowing we are doing the same thing. Write a Symbian App runing on some port,and using J2ME app query the cell id via socket.

Regards cn.caowei@gmail.com

Memory Leaking Issue and Cell ID Issue

Hi caowei,

Thanks for the fix :D im testing it as i type lol

The problem I encountered with the Cell id was that on the mobile operator network I am testing on in Ireland, they were adding data to the transmitted cell id sometimes and sometimes they were not.

For example, in one cell the values would be as follows:

23170 hex = 143728 decimal

but the real cell value should have been

3170 hex = 12656 decimal, which is the correct cell id in decimal.

When I went through the values using the on-device debugger the value was showing up as 0x00023170 as above. I contacted the mobile network operator and they were able to do traces and help me find out the problem and then i programmed around it. It appears the person i was talking to was not sure what the extra value was for but it only happened from certain base stations.

Anyway, so what I had to do was the line of code I showed above:

   //Get the 4 LSB for the Cell ID
   newCellId_1 = CellId & 0xFFFF;

What this does is just puts zeros in the 4 most significant bits of the hex value. So 0x00023170 becomes 0x00003170.

I am testing on a 3G network but then again, i have not fully checked that up and it could be a 2.5G network as im pretty sure that 3 are the only network in Ireland with a proper 3G network and im not using them but as I said, Im not fully sure what their network specs are.

As regards Symbian bugs and Cell Informations, It could be that as I would of thought that my work around that I needed to do for my cell id problem should not of been needed and it should of checked only for the 4 LSB itself without me checking for it.

I have found it other parts of the OS, it ignores zeros when it should not and hence gets the incorrect end value too.

Do you have Carbide Developer or Professional Version? You can step through all the values and see their hex value or decimal value while the app is running if you do.

If not, what you could do to see the hex value is:

TBuf<10> Hex_Value_CellId;

Hex_Value_CellId.Num(CellId, Hex);

And print it out to a log or something.

Seamus

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Article Metadata

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Code Example

Source file: Media:NetworkInfo.zip

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Article

Created: kiran10182 (27 Mar 2007)

Last edited: hamishwillee (26 Jul 2012)

This code example will help you in getting different Network Parameters like: Cell Id, Network Id, Country ID and Network Name.

Warning: Please note that ETel3rdParty (CTelephony) is an API designed to be used asynchronously and that any atempt to do otherwise risks to either panic or freeze your application. In particular, an application using the code presented here will become irresponsive when the phone does not have network connectivity (temprorary signal drop or Offline mode caused by profile change or missing SIM

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NetworkApp.h

#include <e32base.h>
#include <Etel3rdParty.h>
 
class CNetworkApp : public CActive
{
 
private:
        void ConstructL();
        CTelephony* iTelephony;
        CTelephony::TNetworkInfoV1 iNetworkInfoV1;
        CTelephony::TNetworkInfoV1Pckg iNetworkInfoV1Pckg;
 
public:
        CNetworkApp(
                TUint& CellId, TDes& NetworkId, TDes& CountryId, TDes& LongName);
        static void GetNetworkParameters(
                TUint& CellId, TDes& NetworkId, TDes& CountryId, TDes& LongName);
        ~CNetworkApp();
        TUint& iCellID;
        TDes&  iNetworkID;
        TDes&  iCountryCODE;
        TDes&  iLongNAME;
 
private:
        /*
           These are the pure virtual methods from CActive that
           MUST be implemented by all active objects
         */
        void RunL();
        void DoCancel();
};

NetworkApp.cpp

#include "NetworkApp.h"
 
void CNetworkApp::GetNetworkParameters(
        TUint& aCellID, TDes& aNetworkID, TDes& aCountryCODE,
        TDes& aLongName)
{
        CNetworkApp* self=
                new(ELeave) CNetworkApp(
                        aCellID, aNetworkID, aCountryCODE, aLongName);
        CleanupStack::PushL(self);
        self->ConstructL();
        CleanupStack::PopAndDestroy(self);
}
 
void CNetworkApp::ConstructL()
{
        iTelephony = CTelephony::NewL();
        CActiveScheduler::Add(this);        
 
        iTelephony->GetCurrentNetworkInfo(iStatus, iNetworkInfoV1Pckg);
        SetActive();
        CActiveScheduler::Start();
 
}
 
CNetworkApp::CNetworkApp(
        TUint& aCellID,TDes& aNetworkID,TDes& aCountryCODE,TDes& aLongName):
                CActive(EPriorityStandard), iNetworkInfoV1Pckg(iNetworkInfoV1),
                iCellID(aCellID), iNetworkID(aNetworkID), iCountryCODE(aCountryCODE),
                iLongNAME(aLongName)
{
        //default constructor
}
 
void CNetworkApp::RunL()
{
        if(iStatus==KErrNone)
        {
                iCellID = iNetworkInfoV1.iCellId;
                iNetworkID = iNetworkInfoV1.iNetworkId;
                iCountryCODE = iNetworkInfoV1.iCountryCode;
                iLongNAME= iNetworkInfoV1.iLongName;
                CActiveScheduler::Stop();
        }
}
 
void CNetworkApp::DoCancel()
{
        iTelephony->CancelAsync(CTelephony::EGetCurrentNetworkInfoCancel);
}
 
CNetworkApp::~CNetworkApp()
{
        if(iTelephony)
        {
                Cancel();
                delete iTelephony;
                iTelephony = NULL;
        }
}

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Instructions

Now do the following steps:
1) Create a sample "Hello World" type application.
2) Put NetworkApp.h file in your application's "inc" folder.
3) Put NetworkApp.cpp file in your application's "src" folder.
4) Open .mmp file and add entry SOURCE NetworkApp.cpp.
5) Open .mmp file and add entry LIBRARY etel3rdparty.lib.
7) Now you need to include following header in your class to read Network:
#include "NetworkApp.h". Let's say in for e.g.: "CYrAppUi.h"
8) You can then call the static function from any of your Commands.
For ex: in your CYrAppUi.h you need to include "NetworkApp.h"
And Call it like:

case EReadNetworkCommand1:
{
        TUint CellId;
        TBuf<30> NetworkId;
        TBuf<30> CountryId;
        TBuf<30> OperatorLongName;        
        CNetworkApp::GetNetworkParameters(
                CellId, NetworkId, CountryId, OperatorLongName );
 
        TBuf<160> iDisplayString;
        iDisplayString.Format(
                _L( "CellId-%d\nNetworkID-%S\nCountryID-%S\nNETWORK-%S" ),
                 CellId, &NetworkId, &CountryId, &OperatorLongName );
 
        CAknInformationNote* informationNote = new ( ELeave )
                CAknInformationNote;
        informationNote->ExecuteLD(iDisplayString);
}

9) Open .mmp file and add entry CAPABILITY ReadDeviceData.
10) You need to sign resulted .Sis file with your developer certificate to get it installed on your phone.

You can find a working application which can be built with Carbide.c++Here it goes: Network Information.zip

Related Links

• Get the IMEI, IMSI, CellId etc., synchronously on 3.x devices (Blog no longer available, content reproduced below:)

[show details]

In this blog entry I would like to share a small utility class, which is nothing but to find the Phone/Network/Subscriber related information in a synchronous way. In Nokia Developer Technical Library there is already a tip for finding the IMEI number in synchronously, you can find it here. I've just used that approach here to find these details: Phone information: manufacturer, model and serial number (IMEI). You've to basically use the CTelephony::GetPhoneId() API to get these information. Network information: cell id, location area code, country code etc. (this can be extended, check the SDK Help of CTelephony for that). With CTelephony::GetCurrentNetworkInfo() API you can gather the network related information. Notice here you need a ReadDeviceData capability for accessing this function. Subscriber information: subscriber id (IMSI).

The CTelephony::GetSubscriberId() API will help you retrieve this information. All the above functions are not synchronous so to make it synchronous the work-around is the use of CActiveSchedulerWait. After the call of these asynchronous and SetActive() you have to call a iActiveSchedulerWait->Start() and in your RunL() you have to check whether the iActiveSchedulerWait is already started with iActiveSchedulerWait->IsStarted() if then stop by iActiveSchedulerWait->Stop(), then fetch the information.

Get to know more about this please refer this example: DevInfo_3.x. Please check my comments below for more clarity. EDIT: Changed the article name (previously it was Get the IMEI of a 3.x device) and added a more elaborated and extended example.

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