Unigine::Log Class

Example#

The following code demonstrates how to print various types of messages.

Source code (C++)

using namespace Unigine;

// auxiliary variables for messages
const char* file_name = "file.txt";
int ID = 10;

	// reporting an error message
	Log::error("Loading mesh: can't open \"%s\" file\n", file_name);

	// reporting a message
	Log::message("-> Added %d UI elements.\n", ID);

	// reporting a warning message
	Log::warning("ID of the \"%s\" file: %d.\n", file_name, ID);

	// reporting a fatal error message to the log file and closing the application
	Log::fatal("FATAL ERROR reading \"%s\" file!\n", file_name);

Handling Events#

You can subscribe for events to define custom actions on various types of messages printed to the Log. The signature of the handler function must be as follows:

Source code (C++)

void handler_function_name(const char * message_text);

Here is an example of tracking error messages via event handlers:

Source code (C++)

void error_handler(const char * message_text)
{
	std::cout<<"My message is: "<<message_text<<std::endl; 
    // ...
}

// somewhere in the code

// subscribing for the Error event with our handler function
Log::getEventError().connect(error_handler);

// printing an error message to the Log
Log::error("An ERROR has occurred!\n");

Методы:

Имя	Описание View: Sort by:
getEventMessage	The event triggered when a message has been printed to the log.
getEventWarning	The event triggered when a warning has been printed to the log.
getEventError	The event triggered when an error message has been printed to the log.
getEventFatal	The event triggered when a fatal error message has been printed to the log.
error	Prints an error message to the console and the log file.
fatal	Prints a fatal error message to the log file and quits the engine.
message	Prints a message to the console and the log file.
warning	Prints a warning to the console and the log file.

Log Class

Members

Event<const char*> getEventMessage() const#

event triggered when a message has been printed to the log. You can subscribe to events via connect() and unsubscribe via disconnect(). You can also use EventConnection and EventConnections classes for convenience (see examples below).

Usage Example

Source code (C++)

// implement the Message event handler
void message_event_handler(const char * text)
{
	// Handling Message event...
}


//////////////////////////////////////////////////////////////////////////////
//  1. Multiple subscriptions can be linked to an instance of the EventConnections 
//  class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnections class
EventConnections message_event_connections;

// link to this instance when subscribing for an event (subscription for various events can be linked)
Log::getEventMessage().connect(message_event_connections, message_event_handler);

// other subscriptions are also linked to this EventConnections instance 
// (e.g. you can subscribe using lambdas)
Log::getEventMessage().connect(message_event_connections, [](const char * text) { 
		// Handling Message event (lambda)...
	}
);

// ...

// later all of these linked subscriptions can be removed with a single line
message_event_connections.disconnectAll();

//////////////////////////////////////////////////////////////////////////////
//  2. You can subscribe and unsubscribe via an instance of the EventConnection 
//  class. And toggle this particular connection off and on, when necessary.
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnection class
EventConnection message_event_connection;

// subscribe for the Message event with a handler function keeping the connection
Log::getEventMessage().connect(message_event_connection, message_event_handler);

// ...

// you can temporarily disable a particular event connection to perform certain actions
message_event_connection.setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
message_event_connection.setEnabled(true);

// ...

// remove subscription for the Message event via the connection
message_event_connection.disconnect();

//////////////////////////////////////////////////////////////////////////////
//  3. You can add EventConnection/EventConnections instance as a member of the
//  class that handles the event. In this case all linked subscriptions will be 
//  automatically removed when class destructor is called
//////////////////////////////////////////////////////////////////////////////

// Class handling the event
class SomeClass
{
public:
	// instance of the EventConnections class as a class member
	EventConnections e_connections;

	// A Message event handler implemented as a class member
	void event_handler(const char * text)
	{
		// Handling Message event...
		// ...
	}
};

SomeClass *sc = new SomeClass();

// ...

// specify a class instance in case a handler method belongs to some class
Log::getEventMessage().connect(sc->e_connections, sc, &SomeClass::event_handler);

// ...

// handler class instance is deleted with all its subscriptions removed automatically
delete sc;

//////////////////////////////////////////////////////////////////////////////
//  4. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////

// subscribe for the Message event with a handler function
Log::getEventMessage().connect(message_event_handler);


// remove subscription for the Message event later by the handler function
Log::getEventMessage().disconnect(message_event_handler);


//////////////////////////////////////////////////////////////////////////////
//   5. Subscribe to an event saving an ID and unsubscribe later by this ID
//////////////////////////////////////////////////////////////////////////////

// define a connection ID to be used to unsubscribe later
EventConnectionId message_handler_id;

// subscribe for the Message event with a lambda handler function and keeping connection ID
message_handler_id = Log::getEventMessage().connect([](const char * text) { 
		// Handling Message event (lambda)...
	}
);

// remove the subscription later using the ID
Log::getEventMessage().disconnect(message_handler_id);


//////////////////////////////////////////////////////////////////////////////
//   6. Ignoring all Message events when necessary
//////////////////////////////////////////////////////////////////////////////

// you can temporarily disable the event to perform certain actions without triggering it
Log::getEventMessage().setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
Log::getEventMessage().setEnabled(true);

Notice

For more details see the Event Handling article.

The event handler signature is as follows: myhandler(const char * text)

Return value

Event reference.

Event<const char*> getEventWarning() const#

event triggered when a warning has been printed to the log. You can subscribe to events via connect() and unsubscribe via disconnect(). You can also use EventConnection and EventConnections classes for convenience (see examples below).

Usage Example

Source code (C++)

// implement the Warning event handler
void warning_event_handler(const char * text)
{
	// Handling Warning event...
}


//////////////////////////////////////////////////////////////////////////////
//  1. Multiple subscriptions can be linked to an instance of the EventConnections 
//  class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnections class
EventConnections warning_event_connections;

// link to this instance when subscribing for an event (subscription for various events can be linked)
Log::getEventWarning().connect(warning_event_connections, warning_event_handler);

// other subscriptions are also linked to this EventConnections instance 
// (e.g. you can subscribe using lambdas)
Log::getEventWarning().connect(warning_event_connections, [](const char * text) { 
		// Handling Warning event (lambda)...
	}
);

// ...

// later all of these linked subscriptions can be removed with a single line
warning_event_connections.disconnectAll();

//////////////////////////////////////////////////////////////////////////////
//  2. You can subscribe and unsubscribe via an instance of the EventConnection 
//  class. And toggle this particular connection off and on, when necessary.
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnection class
EventConnection warning_event_connection;

// subscribe for the Warning event with a handler function keeping the connection
Log::getEventWarning().connect(warning_event_connection, warning_event_handler);

// ...

// you can temporarily disable a particular event connection to perform certain actions
warning_event_connection.setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
warning_event_connection.setEnabled(true);

// ...

// remove subscription for the Warning event via the connection
warning_event_connection.disconnect();

//////////////////////////////////////////////////////////////////////////////
//  3. You can add EventConnection/EventConnections instance as a member of the
//  class that handles the event. In this case all linked subscriptions will be 
//  automatically removed when class destructor is called
//////////////////////////////////////////////////////////////////////////////

// Class handling the event
class SomeClass
{
public:
	// instance of the EventConnections class as a class member
	EventConnections e_connections;

	// A Warning event handler implemented as a class member
	void event_handler(const char * text)
	{
		// Handling Warning event...
		// ...
	}
};

SomeClass *sc = new SomeClass();

// ...

// specify a class instance in case a handler method belongs to some class
Log::getEventWarning().connect(sc->e_connections, sc, &SomeClass::event_handler);

// ...

// handler class instance is deleted with all its subscriptions removed automatically
delete sc;

//////////////////////////////////////////////////////////////////////////////
//  4. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////

// subscribe for the Warning event with a handler function
Log::getEventWarning().connect(warning_event_handler);


// remove subscription for the Warning event later by the handler function
Log::getEventWarning().disconnect(warning_event_handler);


//////////////////////////////////////////////////////////////////////////////
//   5. Subscribe to an event saving an ID and unsubscribe later by this ID
//////////////////////////////////////////////////////////////////////////////

// define a connection ID to be used to unsubscribe later
EventConnectionId warning_handler_id;

// subscribe for the Warning event with a lambda handler function and keeping connection ID
warning_handler_id = Log::getEventWarning().connect([](const char * text) { 
		// Handling Warning event (lambda)...
	}
);

// remove the subscription later using the ID
Log::getEventWarning().disconnect(warning_handler_id);


//////////////////////////////////////////////////////////////////////////////
//   6. Ignoring all Warning events when necessary
//////////////////////////////////////////////////////////////////////////////

// you can temporarily disable the event to perform certain actions without triggering it
Log::getEventWarning().setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
Log::getEventWarning().setEnabled(true);

Notice

For more details see the Event Handling article.

The event handler signature is as follows: myhandler(const char * text)

Return value

Event reference.

Event<const char*> getEventError() const#

event triggered when an error message has been printed to the log. You can subscribe to events via connect() and unsubscribe via disconnect(). You can also use EventConnection and EventConnections classes for convenience (see examples below).

Usage Example

Source code (C++)

// implement the Error event handler
void error_event_handler(const char * text)
{
	// Handling Error event...
}


//////////////////////////////////////////////////////////////////////////////
//  1. Multiple subscriptions can be linked to an instance of the EventConnections 
//  class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnections class
EventConnections error_event_connections;

// link to this instance when subscribing for an event (subscription for various events can be linked)
Log::getEventError().connect(error_event_connections, error_event_handler);

// other subscriptions are also linked to this EventConnections instance 
// (e.g. you can subscribe using lambdas)
Log::getEventError().connect(error_event_connections, [](const char * text) { 
		// Handling Error event (lambda)...
	}
);

// ...

// later all of these linked subscriptions can be removed with a single line
error_event_connections.disconnectAll();

//////////////////////////////////////////////////////////////////////////////
//  2. You can subscribe and unsubscribe via an instance of the EventConnection 
//  class. And toggle this particular connection off and on, when necessary.
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnection class
EventConnection error_event_connection;

// subscribe for the Error event with a handler function keeping the connection
Log::getEventError().connect(error_event_connection, error_event_handler);

// ...

// you can temporarily disable a particular event connection to perform certain actions
error_event_connection.setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
error_event_connection.setEnabled(true);

// ...

// remove subscription for the Error event via the connection
error_event_connection.disconnect();

//////////////////////////////////////////////////////////////////////////////
//  3. You can add EventConnection/EventConnections instance as a member of the
//  class that handles the event. In this case all linked subscriptions will be 
//  automatically removed when class destructor is called
//////////////////////////////////////////////////////////////////////////////

// Class handling the event
class SomeClass
{
public:
	// instance of the EventConnections class as a class member
	EventConnections e_connections;

	// A Error event handler implemented as a class member
	void event_handler(const char * text)
	{
		// Handling Error event...
		// ...
	}
};

SomeClass *sc = new SomeClass();

// ...

// specify a class instance in case a handler method belongs to some class
Log::getEventError().connect(sc->e_connections, sc, &SomeClass::event_handler);

// ...

// handler class instance is deleted with all its subscriptions removed automatically
delete sc;

//////////////////////////////////////////////////////////////////////////////
//  4. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////

// subscribe for the Error event with a handler function
Log::getEventError().connect(error_event_handler);


// remove subscription for the Error event later by the handler function
Log::getEventError().disconnect(error_event_handler);


//////////////////////////////////////////////////////////////////////////////
//   5. Subscribe to an event saving an ID and unsubscribe later by this ID
//////////////////////////////////////////////////////////////////////////////

// define a connection ID to be used to unsubscribe later
EventConnectionId error_handler_id;

// subscribe for the Error event with a lambda handler function and keeping connection ID
error_handler_id = Log::getEventError().connect([](const char * text) { 
		// Handling Error event (lambda)...
	}
);

// remove the subscription later using the ID
Log::getEventError().disconnect(error_handler_id);


//////////////////////////////////////////////////////////////////////////////
//   6. Ignoring all Error events when necessary
//////////////////////////////////////////////////////////////////////////////

// you can temporarily disable the event to perform certain actions without triggering it
Log::getEventError().setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
Log::getEventError().setEnabled(true);

Notice

For more details see the Event Handling article.

The event handler signature is as follows: myhandler(const char * text)

Return value

Event reference.

Event<const char*> getEventFatal() const#

event triggered when a fatal error message has been printed to the log. You can subscribe to events via connect() and unsubscribe via disconnect(). You can also use EventConnection and EventConnections classes for convenience (see examples below).

Usage Example

Source code (C++)

// implement the Fatal event handler
void fatal_event_handler(const char * text)
{
	// Handling Fatal event...
}


//////////////////////////////////////////////////////////////////////////////
//  1. Multiple subscriptions can be linked to an instance of the EventConnections 
//  class that you can use later to remove all these subscriptions at once
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnections class
EventConnections fatal_event_connections;

// link to this instance when subscribing for an event (subscription for various events can be linked)
Log::getEventFatal().connect(fatal_event_connections, fatal_event_handler);

// other subscriptions are also linked to this EventConnections instance 
// (e.g. you can subscribe using lambdas)
Log::getEventFatal().connect(fatal_event_connections, [](const char * text) { 
		// Handling Fatal event (lambda)...
	}
);

// ...

// later all of these linked subscriptions can be removed with a single line
fatal_event_connections.disconnectAll();

//////////////////////////////////////////////////////////////////////////////
//  2. You can subscribe and unsubscribe via an instance of the EventConnection 
//  class. And toggle this particular connection off and on, when necessary.
//////////////////////////////////////////////////////////////////////////////

// create an instance of the EventConnection class
EventConnection fatal_event_connection;

// subscribe for the Fatal event with a handler function keeping the connection
Log::getEventFatal().connect(fatal_event_connection, fatal_event_handler);

// ...

// you can temporarily disable a particular event connection to perform certain actions
fatal_event_connection.setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
fatal_event_connection.setEnabled(true);

// ...

// remove subscription for the Fatal event via the connection
fatal_event_connection.disconnect();

//////////////////////////////////////////////////////////////////////////////
//  3. You can add EventConnection/EventConnections instance as a member of the
//  class that handles the event. In this case all linked subscriptions will be 
//  automatically removed when class destructor is called
//////////////////////////////////////////////////////////////////////////////

// Class handling the event
class SomeClass
{
public:
	// instance of the EventConnections class as a class member
	EventConnections e_connections;

	// A Fatal event handler implemented as a class member
	void event_handler(const char * text)
	{
		// Handling Fatal event...
		// ...
	}
};

SomeClass *sc = new SomeClass();

// ...

// specify a class instance in case a handler method belongs to some class
Log::getEventFatal().connect(sc->e_connections, sc, &SomeClass::event_handler);

// ...

// handler class instance is deleted with all its subscriptions removed automatically
delete sc;

//////////////////////////////////////////////////////////////////////////////
//  4. You can subscribe and unsubscribe via the handler function directly
//////////////////////////////////////////////////////////////////////////////

// subscribe for the Fatal event with a handler function
Log::getEventFatal().connect(fatal_event_handler);


// remove subscription for the Fatal event later by the handler function
Log::getEventFatal().disconnect(fatal_event_handler);


//////////////////////////////////////////////////////////////////////////////
//   5. Subscribe to an event saving an ID and unsubscribe later by this ID
//////////////////////////////////////////////////////////////////////////////

// define a connection ID to be used to unsubscribe later
EventConnectionId fatal_handler_id;

// subscribe for the Fatal event with a lambda handler function and keeping connection ID
fatal_handler_id = Log::getEventFatal().connect([](const char * text) { 
		// Handling Fatal event (lambda)...
	}
);

// remove the subscription later using the ID
Log::getEventFatal().disconnect(fatal_handler_id);


//////////////////////////////////////////////////////////////////////////////
//   6. Ignoring all Fatal events when necessary
//////////////////////////////////////////////////////////////////////////////

// you can temporarily disable the event to perform certain actions without triggering it
Log::getEventFatal().setEnabled(false);

// ... actions to be performed

// and enable it back when necessary
Log::getEventFatal().setEnabled(true);

Notice

For more details see the Event Handling article.

The event handler signature is as follows: myhandler(const char * text)

Return value

Event reference.

void error ( const char * format, ... ) #

Prints an error message to the console and the log file.

Arguments

const char * format - Error message to print.
... - Arguments, multiple allowed.

void fatal ( const char * format, ... ) #

Prints a fatal error message to the log file and quits the engine.

Arguments

const char * format - Fatal error message to print.
... - Arguments, multiple allowed.

void message ( const char * format, ... ) #

Prints a message to the console and the log file.

Arguments

const char * format - Message to print.
... - Arguments, multiple allowed.

void warning ( const char * format, ... ) #

Prints a warning to the console and the log file.

Arguments

const char * format - Warning to print.
... - Arguments, multiple allowed.

Last update: 16.08.2024

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Unigine::Log Class

In This Article:

Example#

Handling Events#

Методы:

Log Class

Members

Event<const char*> getEventMessage() const#

Return value

Event<const char*> getEventWarning() const#

Return value

Event<const char*> getEventError() const#

Return value

Event<const char*> getEventFatal() const#

Return value

void error ( const char * format, ... ) #

Arguments

void fatal ( const char * format, ... ) #

Arguments

void message ( const char * format, ... ) #

Arguments

void warning ( const char * format, ... ) #

Arguments