class KUniqueApplication

# class KUniqueApplication | Maintains only a single instance of a running application at a time. More...
Definition | `#include <kuniqueapplication.h>`
Inherits | DCOPObject (dcop) [public ], KApplication [public ]
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#### Public Methods

- KUniqueApplication ( bool allowStyles=true, bool GUIenabled=true, bool configUnique=false)
- virtual ~KUniqueApplication ()
- bool process (const QCString &fun, const QByteArray &data, QCString &replyType, QByteArray &replyData)
- virtual int newInstance ()

#### Public Static Methods

- static void addCmdLineOptions ()
- static bool start ()

#### Protected Methods

- virtual void virtual_hook ( int id, void* data )

## Detailed Description

Maintains only a single instance of a running application at a time.

If another instance is started, it will determine (via DCOP) whether it is the first instance or a second instance. If it is a second instance, it will forward on the information to the first instance and then quit.

See also: KApplication, DCOPObject

KUniqueApplication ( bool allowStyles=true, bool GUIenabled=true, bool configUnique=false) | ### KUniqueApplication

Constructor. Takes command line arguments from KCmdLineArgs

Parameters:

allowStyles | Set to false to disable the loading on plugin based styles. This is only useful to applications that do not display a GUI normally. If you do create an application with `allowStyles` set to false it normally runs in the background but under special circumstances displays widgets. Call KApplication::enableStyles() before displaying any widgets.
GUIenabled | Set to false to disable all GUI stuff. This implies no styles either.
configUnique | If true, the uniqueness of the application will depend on the value of the "MultipleInstances" key in the "KDE" group of the application config file.

void addCmdLineOptions () | ### addCmdLineOptions

[static]

Adds command line options specific for KUniqueApplication.

Should be called before calling KUniqueApplication constructor and / or start().

Reimplemented from KApplication.

bool start () | ### start

[static]

Forks and registers with dcop.

The command line arguments are being sent via DCOP to newInstance() and will be received once the application enters the event loop.

Typically this is used like:

     int main(int argc, char **argv) {
        KAboutData about("myappname", "myAppName", .....);
        KCmdLineArgs::init(argc, argv, &about);
        KCmdLineArgs::addCmdLineOptions( myCmdOptions );
        KUniqueApplication::addCmdLineOptions();

        if (!KUniqueApplication::start()) {
           fprintf(stderr, "myAppName is already running!\n");
           exit(0);
        }
        KUniqueApplication a;
        a.exec();
     }

Note that it's not necessary to call start() explicitly. It will be called automatically before creating KUniqueApplication if it hasn't been called yet, without any performance impact.

Returns: true if registration is succesful. false if another process was already running.

~KUniqueApplication () | ### ~KUniqueApplication

[virtual]

Destructor

bool process (const QCString &fun, const QByteArray &data, QCString &replyType, QByteArray &replyData) | ### process

Dispatches any incoming DCOP message for a new instance.

If it is not a request for a new instance, return false. Overloaded from DCOPObject to make sure that the application stays unique.

Parameters:

fun | DCOP function signature
data | the data for the arguments
replyType | the type of the reply value
replyData | the reply

See also: DCOPObject

Reimplemented from DCOPObject.

int newInstance () | ### newInstance

[virtual]

Creates a new "instance" of the application.

Usually this will involve making some calls into the GUI portion of your application asking for a new window to be created, possibly with some data already loaded based on the arguments received.

Command line arguments have been passed to KCmdLineArgs before this function is called and can be checked in the usual way.

Note that newInstance() is called also in the first started application process.

Returns: An exit value. The calling process will exit with this value.

void virtual_hook ( int id, void* data ) | ### virtual_hook

[protected virtual]

Reimplemented from KApplication.

- Author: Preston Brown
- Generated: root on macppc.ports.openbsd.org on Sat Sep 6 10:36:15 2003, using kdoc 2.0a54.