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char*buffer;
constintbufferlength =GEVI_MAXACTIONLENGTH;
intnumBytesReceived;
buffer=newchar[bufferlength];
gevimessage- >WriteASCIIMessage (buffer,
bufferlength,
numBytesReceived);
std::cout <<buffer<<std::endl;
4.Example ofcreating aGeViScope Action Message
GeViScope messages canalsobecreatedinsideGeViSoftdirectly.Thisisneededtoallow
theinteroperability ofGeViSoftandGeViScope.
TheGeViScope messageconstructors canbefoundintheGscActions header.Theyare
implemented insidetheGscActions DLL.GscActions canbecreatedbycallingtheCActG-
scActionconstructor:
CGeViMessage* gevimessage =newCActGscAction ( 
"YourGscServerName" ,
GscAct_CreateCustomAction (1,L"HelloGeViScope!" ));
 NOTICE
Pleasenotethat“GscServerNameAlias” isthealiasnameyouconfigured fortheconnection in
GeViSet.
Sending ActionMessages
ThenextexampleshowsyouhowtosendamessagetotheGeViSoftserver.Asapre-
requisite,aGeViAPIClient objectmustalreadybecreatedandconnected totheserver.
C++Example:
GeViAPIClient* m_APIClient

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//mustalready becreated andconnected
/*
…
*/
CGeViMessage* gevimessage =newCActCustomAction (
123,"HelloGeViSoft!" );
if(gevimessage)
{
m_APIClient- >SendMessage (gevimessage);
//Don’tforgettodeleteobjects youcreateinsidetheDLL
gevimessage- >DeleteObject ();
}
Receiving ActionMessages
ThisexampleshowsyouhowtoreceiveamessagefromGeViSoft. Asaprerequisite, aGeVi-
APIClient objectmustalreadybecreatedandconnected totheserver.Furthermore, adata-
basenotification callbackfunctionmustbedefined.Thiscallbackfunctionwillbecalledfrom
insidetheGeViProcAPI DLLwhenever anotification fromtheserverisreceived.
Pseudo code
1.Definethecallback
2.Definethecallback’s handlermethod
3.RegisteryourcallbackwiththeGeViAPIClient connection’s object.
4.Handlethereceivednotifications inyouhandlermethod.
C++Example:
1.Define thecallback

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void__stdcall GeViDatabaseNotificationCB (void*Instance,
TServerNotification Notification,
void*Params)
{
if(Instance ==NULL)
return;
//calling thecallback methodofyourClass object's instance.
//Asanexample, CYourClass mightbeCMainWin foranMFCApplication
CYourClass* yourClass =(CYourClass*) Instance;
yourClass- >DatabaseNotification (Notification, Params);
}
2.Define thecallback’s method
voidDatabaseNotification (TServerNotification Notification,
void*Params)
{
//Checkifwereceived amessage. Itmightalsobeanother
//notification likeachangeofsetuporshutdown oftheserver
if(Notification ==NFServer_ NewMessage)
{
//createthemessage ifpossible
//(themessage isfreedagaininthemainthreadcontext)
CGeViMessage* gevimessage;
TMessageEntry* messageEntry =
reinterpret_ cast<TMessageEntry*> (Params);
intnoOfBytesRead =0;
gevimessage =CGeViMessage::ReadBinMessage (
messageEntry- >Buffer,
messageEntry- >Length,
noOfBytesRead);
if(gevimessage)
{
//Youreceived amessage! Nowyouneedtohandleit.
//Thiscanbedonehere.
}
else

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{
//Message couldnotbecreated. Handletheerrorhere.
}
}
else
{
//Ifwearehere,wereceived another typeofnotification
}
}
3.Register yourcallback withtheconnection object.
m_APIClient =newGeViAPIClient ( ...);
if(m_APIClient)
{
//connect totheserver
TConnectResult ConnectResult =
m_APIClient- >Connect (ConnectProgressCB, this);
if(ConnectResult ==connectOk)
{
//Connection established! Nowregister yourcallback!
m_APIClient- >SetCBNotification (
GeViDatabaseNotificationCB, this);
}
}
Disconnecting fromaGeViServer
Whendisconnecting fromtheserver,youshouldunregister yournotification callbackand
deletetheGeViAPIClient object.
C++Example:
voidDisconnectFromServer ()
{

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if(m_APIClient !=NULL)
{
//Unregister thenotification callback
m_APIClient- >SetCBNotification (NULL,NULL);
m_APIClient- >Disconnect ();
deletem_APIClient;
m_APIClient =NULL;
}
}

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StateQueries
StateQueriesaremessages sentfromtheclienttotheservertogetinformation aboutthe
stateoflogicalandphysicalcomponents oftheGeViSoftsystemwellasvirtualressources.
Anexampleofsuchinformation wouldbeanenumeration ofallthevideoinputsavailableata
GeViServer.
Creating StateQueries
Youcancreateastatequerybycallingitspredefined constructor. Allthestatequeries’con-
structorsarelocatedintheStateQueries header,C++,andPascalfiles.
StatequeriescanthenbesentwiththeSendStateQuery ()methodoftheGeViAPIClient
class.ThismethodreturnsaCStateAnswer objectwiththeGeViServer’s response.
CStateAnswer* StateAnswer =m_APIClient- >SendStateQuery (
GetFirstVideoInputQuery, INFINITE);
Thesecondparameter ofthemethodisthetimeoutforaserveranswerinmilliseconds. By
sendingINFINITE,youcanpreventthecallfromtimingout.
Creating, sending, andreceiving statequeries isimplemented intheSDK’sexam-
pleDelphi/CPP_ SimpleClient.
Enumeration ofallvideoinputs
Pseudo code
1.Createastatequerytogetthefirstvideoinput(classCSQGetFirstVideoInput)
2.Sendthequerytotheserver

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3.If theanswerisavalidinputchannelthen
4.REPEAT
a)Gettheactualchannel’s  information fromtheanswerandprocessitasneeded(e.g.
printitout,storeittoalist)
b)CreateastatequerytogetthenextvideoInput(classCSQGetNextVideoInput)
c)Sendthequery
5.UNTILthereisnomorevideoinputleft
C++Example:
voidCMainWin::FillVideoInputsList ()
{
if(m_APIClient ==NULL)
return;
//Enumerate allavailable videoinputswiththehelpofstatequeries.
//Createanewstatequerythatwillreturnthefirstvideoinputchan-
nel:
CStateQuery* getFirstVideoInputQuery =newCSQGetFirstVideoInput (
true,//showonlyactivechannels
true);//showonlyenabled channels
if(getFirstVideoInputQuery)
{
//Sendthequerytotheserver
CStateAnswer* stateAnswer =m_APIClient- >SendStateQuery (
getFirstVideoInputQuery,
INFINITE); //Timeout
//Don'tforgettofreethememoryinsidetheDLL...
getFirstVideoInputQuery- >DeleteObject ();
if(stateAnswer)
{
//Iterate through allavailable videoinputchannels

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while(stateAnswer- >m_AnswerKind !=sak_Nothing)
{
//Getthechannels info
CSAVideoInputInfo* videoInputInfo =
reinterpret_ cast<CSAVideoInputInfo*> (stateAnswer);
//createavideoinputdescriptor
TVideoInputDescriptor* newVideoInput =new
TVideoInputDescriptor (videoInputInfo- >m_GlobalID,
videoInputInfo- >m_Name,
videoInputInfo- >m_Description,
videoInputInfo- >m_HasPTZHead,
videoInputInfo- >m_HasVideoSensor,
videoInputInfo- >m_HasContrastDetection,
videoInputInfo- >m_HasSyncDetection);
//Dosomething withthechannel information. Here:
//Addthechannel information toa
//CListBox lbVideoInputs
intnewIndex =lbVideoInputs.AddString (
newVideoInput- >m_Name.c_str());
lbVideoInputs.SetItemDataPtr (newIndex, newVideoInput);
//Createaquerytogetthenextinputchannel
CStateQuery* getNextVideoInputQuery =new
CSQGetNextVideoInput (true,true,
videoInputInfo- >m_GlobalID);
stateAnswer- >DeleteObject ();
stateAnswer =NULL;
if(getNextVideoInputQuery)
{
stateAnswer =
m_APIClient- >SendStateQuery (
getNextVideoInputQuery, INFINITE);
getNextVideoInputQuery- >DeleteObject ();
if(!stateAnswer)
break;
}
else//Nomorevideoinputchannel detected!
break;
}
if(stateAnswer)

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{
stateAnswer- >DeleteObject ();
stateAnswer =NULL;
}
}
}
}

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Database Queries (optional)
Database queriesallowyoutofetchdatasetsfromtheactionoralarmtableoftheGeViSoft
activitydatabase. Alltheactionsthathavebeenreceivedandallthealarmeventsthat
occurredarestoredinsidethedatabase. Tospecifyandnarrowdownyourqueryresults,sev-
eralfilteroperations areavailableaswell.
Togetfamiliar withthepossibilities ofGeViSoft’s database queries, andespe-
ciallyitsfiltering options, please havealookattheGeViAPI TestClient’s “Data-
baseViewer” and“Database Filter” tabs.
Creating Database Queries
Youcancreateadatabasequerybycallingitspredefined constructor. Allthedatabaseque-
ries’constructors arelocatedintheDatabaseQueries header,C++,andPascalfiles.
Database queriescanthenbesentwiththeSendDatabaseQuery ()methodoftheGeVi-
APIClient class.ThismethodreturnsaCDataBaseAnswer objectwiththeGeViServer’s
response.
CDataBaseQuery* geviquery =newCDBQCreateActionQuery (0);
CDataBaseAnswer* dbAnswer =m_APIClient- >SendDatabaseQuery (geviquery, INFI-
NITE);
Thesecondparameter ofthemethodisthetimeoutforaserveranswerinmilliseconds. By
sendingINFINITE,youcanpreventthecallfromtimingout.
Database QuerySession Handling
Actionsendingandstatequeryingdidnotneedanyformofsessionhandling.Thisisdifferent
fordatabasequerying.Usuallyyouwanttocollectseveralrecordsthatareconnected in