From Forum Nokia Wiki

ID	TSS000649	Creation date	May 10, 2007
Platform	S60 1st Edition S60 2nd Edition and FP1, FP2, FP3 S60 3rd Edition and FP1 Series 80 2nd Edition	Devices
Category	Symbian C++	Subcategory	Base & System, Application Framework

Keywords (APIs, classes, methods, functions):

Overview

Retrieving a list of currently running tasks

Description

Application framework in Symbian OS provides APIs for retrieving information about the tasks that are currently running either in foreground or background.

Solution

A list of currently running tasks can be retrieved with TApaTaskList class. A task is identified by its association with the running application’s window group. A session to the window server needs to be passed to TApaTaskList during construction.
#include <apgtask.h>    // link against apgrfx.lib
    TApaTaskList tasklist(CCoeEnv::Static()->WsSession());
    TApaTask taskInForeground = tasklist.FindByPos( 0 );
    // Window Group ID of the foreground task
    TInt WindowGroupIdentifier = taskInForeground.WgId();
    // Thread ID of the foreground task
    TThreadId ThreadIdentifier = taskInForeground.ThreadId();
The first task in TApaTaskList is the one in foreground (the associated window group has ordinal position 0).
TApaTask contains some information about the task. For example, the thread identifier (ThreadId()) and window group identifier (WgId()).
Furthermore, there are useful methods such as EndTask() that requests the task to close normally, and KillTask() that directly terminates the task. SendToBackground() and BringToForeground() can be used for controlling the application’s position in the task list.