Archived:Discovering Bluetooth devices using Symbian C++

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Article Metadata

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Tested with

Devices(s): Nokia N95

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Compatibility

Platform(s): S60 3rd Edition, MR

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Article

Keywords: RHostResolver, RSocketServ, TInquirySockAddr, RHostResolver::GetByAddress(), RSocketServ::FindProtocol()

Created: tepaa (24 Apr 2008)

Last edited: lpvalente (25 Aug 2012)

Overview

This article shows how to search Bluetooth devices with RHostResolver.

RHostResolver provides an interface to host name resolution services, such as DNS, that may be provided by certain protocol modules.

The interface provides functions to access the following facilities:

• Obtaining names from addresses
• Obtaining addresses from names
• Getting and setting local host name

Before using any service, a connection to a socket server session must be established.

Each function is available in both synchronous and asynchronous versions.

MMP file

The following capabilities and libraries are required:

CAPABILITY LocalServices
LIBRARY esock.lib
LIBRARY bluetooth.lib

Header file

#include <es_sock.h>
#include <bt_sock.h>
 
RSocketServ iSocketServ;
RHostResolver iResolver;
TInquirySockAddr iAddr;

Source file

CMyDeviceDiscoverer must be an active object (derived from CActive).

_LIT(KBTLinkManagerTxt,"BTLinkManager");
 
 
void CMyDeviceDiscoverer::ConstructL()
    {
    ...
    // Get socket server session
    User::LeaveIfError(iSocketServ.Connect());
    ...
    }
 
void CMyDeviceDiscoverer::DiscoverDevicesL()
    {
    if (!IsActive())
        {
        // Load protocol for discovery
        TProtocolDesc pdesc;
        User::LeaveIfError(
            iSocketServ.FindProtocol(KBTLinkManagerTxt(), pdesc));
 
        // Initialize host resolver
        iResolver.Close();
        User::LeaveIfError(
            iResolver.Open(iSocketServ, pdesc.iAddrFamily, pdesc.iProtocol));
 
        // Start device discovery by invoking remote address lookup
        iAddr.SetIAC( KGIAC );
        iAddr.SetAction(KHostResInquiry|KHostResName|KHostResIgnoreCache);
        iResolver.GetByAddress(iAddr, iEntry, iStatus);
        SetActive();
        }
    else
        {
        User::Leave(KErrNotReady);
        }
    }
 
void CMyDeviceDiscoverer::RunL()
    {
    // RHostResolver.GetByAddress() has completed, process results
 
    if ( iStatus!=KErrNone )
        {
        // All devices find
        }
    else 
        {
        // New device data entry
 
        // Device name
        iEntry().iName;
 
        // Device address
        static_cast<TBTSockAddr>(iEntry().iAddr).BTAddr();
 
        // Get next discovered device
        iResolver.Next(iEntry, iStatus);
        SetActive();
        }
    }
 
void CMyDeviceDiscoverer::DoCancel()
    {
    iResolver.Cancel();
    }
 
CMyDeviceDiscoverer::~CMyDeviceDiscoverer()
    { 
    Cancel();
    iResolver.Close();
    }

Postconditions

CMyDeviceDiscoverer finds existing Bluetooth devices.

See also

Archived:Discovering Bluetooth services using Symbian C++

Advertising Bluetooth services using Symbian C++

Archived:Establishing a Bluetooth connection using Symbian C++

Archived:RHostResolver and redundant display of access point selection dialog (Known Issue)

Example application

This code snippet has been used in the S60 Platform: Bluetooth Point-to-multipoint Example application.