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<concept id="GUID-4E195F2A-78AE-5664-A115-AD65BF457AB1" xml:lang="en"><title>System

Monitor</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The System Monitor (SysMon) provides a Process Monitor and Restart service.

Its clients are typically the System Starter and After Market Starter which

use information in static and dynamic startup configurations (SSC & DSC)

to set the restart parameters. </p>

<p>An application or process may also add itself to the System Monitor's list. </p>

<p>Use of the System Monitor API is restricted by capabilites of the client: </p>

<ul>

<li id="GUID-8F39C454-1FDB-5907-B189-234EE3F61EF1"><p> <b>WriteDeviceData</b> is

required to request a process restart, </p> </li>

<li id="GUID-0DB11E09-A380-5522-8385-5D439CCC9774"><p> <b>ProtServ</b> is

required to request an OS restart into Normal mode </p> </li>

<li id="GUID-82701B6E-BBBE-5925-8D20-871C21AB94D5"><p> <b> PowerMgmt</b> is

required to request a restart into Startup mode </p> </li>

</ul>

<p>The system monitor API is simple and self explanatory. A client must instantiate

an <xref href="GUID-19467402-8575-33F0-817D-339D39982D39.dita"><apiname>RSysMonSession</apiname></xref>, connect to the SysMon server and open

[the session]. </p>

<codeblock id="GUID-2017D6A5-BA32-5DAC-820A-A862A0F381B8" xml:space="preserve">

// sysmonclisess.h

//

// Copyright (c) 2006 Symbian Software Ltd.  All rights reserved.

//

#include <e32std.h>

#include <e32base.h>

#include <startupproperties.h>

#include "startup.hrh"

class RSysMonSession : public RSessionBase

{

public:

    IMPORT_C TInt Open() ;

    IMPORT_C void Close() ;

    IMPORT_C TInt MonitorL(CStartupProperties& aStartupProperties, RProcess& aProcess) ;    

    IMPORT_C TInt MonitorSelfL(CStartupProperties& aStartupProperties) ;

    IMPORT_C TInt CancelMonitorSelf() ;    

} ;</codeblock>

<p>Monitoring is started with a call to <codeph>MonitorL()</codeph> or <codeph>MonitorSelfL()</codeph>.

Before calling one of these functions, however, a <xref href="GUID-90F95A8A-A901-3987-99ED-57F1A57F1C09.dita"><apiname>CStartupProperties</apiname></xref> object

must be created and populated with the desired monitoring and restart configuration. </p>

<p> <xref href="GUID-90F95A8A-A901-3987-99ED-57F1A57F1C09.dita"><apiname>CStartupProperties</apiname></xref> has a series of <codeph>Set...()</codeph> functions

which are used to determine the monitoring and restart behaviour for the application

or process to be monitored. It has a version number (returned by the <codeph>Version()</codeph> function)

as it is designed to remain compatible with future Symbian extensions. </p>

<p>The following snippet shows how a process might add itself to SysMon, specifying

that it should be restarted in the event of failure and that, if it cannot

be restarted, the device should be rebooted. </p>

<codeblock id="GUID-AE7B448B-BDC6-53D3-A429-3B28E5638DD5" xml:space="preserve">

...

// Add this application to SysMon.

// (Note that this is normally done by SysStart or AmaStarter using information in an SSC or DSC.)

RSysMonSession sysMon ;

TInt err = sysMon.Connect() ;

   // handle error

err = sysMon.Open() ;

   // handle error

_LIT( KFileName, "Z:\\sys\\bin\\myServ.exe" ) ;

_LIT( KRestartArg, "-restart" ) ; 

CStartupProperties startupProperties = CStartupProperties::NewLC( KFileName, KRestartArg ) ;

startupProperties->SetStartupType( EStartProcess) ; // TStartupType

startupProperties->SetStartMethod( EWaitForStart ) ; // TStartMethod

startupProperties->SetNumberOfRetries( KRetryCount ) ;

startupProperties->SetTimeout( KRestartTimeout ) ; // timeout in milliseconds

startupProperties->SetRecoveryParams( ERestartOS , KNormalMode ) ;  // TRecoveryMethod, modes are device specific  

startupProperties->SetMonitored( ETrue ) ; // montoring enabled

startupProperties->SetViewless( ETrue ) ;

startupProperties->SetStartInBackground( ETrue ) ;

err = sysMon.MonitorSelfL( *startupProperties ) ;

   // handle error

CleanupStack::PopAndDestroy( startupProperties ) ;

sysMon.Close() ;

...

</codeblock>

<p><b>Setting up Monitoring in an SSC </b> </p>

<p>Process monitoring is normally configured for processes and applications

using <xref href="GUID-F118988C-47C9-3AF0-BCD2-150CAA5508C3.dita"><apiname>START_PROCESS_INFO2</apiname></xref> and <xref href="GUID-FFC386AF-61B6-39F8-90BB-5AD94190E5D6.dita"><apiname>START_APP_INFO2</apiname></xref> resources

in an SSC. These are defined in <filepath>sysstart.rh</filepath>. </p>

<p>Note that these structures add <b>monitor</b>, <b>startup mode</b> and

a <b>localisable error message</b> to <xref href="GUID-41FDADC6-D207-341F-BA5E-BF7F9CF99601.dita"><apiname>START_PROCESS_INFO</apiname></xref> and <xref href="GUID-4CE505AC-FDD9-3155-8141-C54C5EEB259E.dita"><apiname>START_APP_INFO</apiname></xref>. </p>

<codeblock id="GUID-5E4F5ED2-DE43-51D1-A99C-A8864376C2BC" xml:space="preserve">

STRUCT START_PROCESS_INFO2                  // For starting processes

    {

    WORD type = EStartupProcess2;           // do not change

    LTEXT path = "";                        // VALUE REQUIRED

    LTEXT args = "";                        // Passed to the command line of the started process

    WORD start_method = EFireAndForget;     // can also be EWaitForStart or EDeferredWaitForStart

    LONG timeout = 0;                       // In milliseconds only used for EWaitForStart

    WORD retry_failure_recovery_method = ERestartOS;     // can be EIgnoreCommandFailure

    WORD no_of_retries_on_failure = 0;      // only used for EWaitForStart

    WORD monitor = 0;                       // can be 1 if monitoring required

    WORD retry_failure_recovery_startup_mode = -1;

    LTEXT localisable_resource_file="";

    LONG localisable_resource_id=0;         // used when fail_on_error= EinformUserOnFailure

    }

</codeblock>

<codeblock id="GUID-73B02FE6-928F-55DF-9139-93355D04CFC5" xml:space="preserve">

STRUCT START_APP_INFO2                      // For starting apps

    {

    WORD type = EStartupApp2;               // do not change

    LTEXT path = "";                        // VALUE REQUIRED

    LTEXT args = "";                        // Ignored

    WORD start_method = EFireAndForget;     // can also be EWaitForStart or EDeferredWaitForStart

    WORD viewless = 0;                      // can be 1

    WORD start_in_background = 0;           // can be 1

    LONG timeout = 0;                       // In milliseconds only used for EWaitForStart

    WORD retry_failure_recovery_method = ERestartOS;     // can be EIgnoreCommandFailure

    WORD no_of_retries_on_failure = 0;      // only used for EWaitForStart

    WORD monitor = 0;                       // can be 1 if monitoring required

    WORD retry_failure_recovery_startup_mode = -1;

    LTEXT localisable_resource_file="";

    LONG localisable_resource_id=0;         // used when fail_on_error= EinformUserOnFailure

    }

</codeblock>

<p><b>Setting up Monitoring in a DSC </b> </p>

<p>Aftermarket components started at boot

using a <xref href="GUID-E3941FAF-988E-5FB3-8E62-84E192E41EA1.dita">Dynamic Startup

Configuration (DSC)</xref> may also be monitored and restarted by SysMon.

The DSC API uses <xref href="GUID-90F95A8A-A901-3987-99ED-57F1A57F1C09.dita"><apiname>CStartupProperties</apiname></xref> in the manner described

above. An AMC may be restarted on failure but it will not be permitted to

reboot the device. </p>

</conbody></concept>