---
name: "SoEventCallback"
section: "3iv"
platform: "linux"
package: "inventor-doc"
version: "2.1.6+ds-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/SoEventCallback/3iv"
---

# SoEventCallback(3iv)

node which invokes callbacks for events

## NAME

SoEventCallback — node which invokes callbacks for events

## INHERITS FROM

SoBase \> SoFieldContainer \> SoNode \> SoEventCallback

## SYNOPSIS

**#include \<Inventor/nodes/SoEventCallback.h\>**

**typedef void**	**SoEventCallbackCB(void \*userData, SoEventCallback \*node)**

Methods from class SoEventCallback:

**static SoType**	**getClassTypeId()**\
 	**SoEventCallback()**\
 **void**	**setPath(SoPath \*path)**\
 **const SoPath \***	**getPath()**\
 **void**	**addEventCallback(SoType eventType, SoEventCallbackCB \*f, void \*userData = NULL)**\
 **void**	**removeEventCallback(SoType eventType, SoEventCallbackCB \*f, void \*userData = NULL)**\
 **SoHandleEventAction \***	**getAction() const**\
 **const SoEvent \***	**getEvent() const**\
 **const SoPickedPoint \***	**getPickedPoint() const**\
 **void**	**setHandled()**\
 **SbBool**	**isHandled() const**\
 **void**	**grabEvents()**\
 **void**	**releaseEvents()**

Methods from class SoNode:

**void**	**setOverride(SbBool state)**\
 **SbBool**	**isOverride() const**\
 **SoNode \***	**copy(SbBool copyConnections = FALSE) const**\
 **virtual SbBool**	**affectsState() const**\
 **static SoNode \***	**getByName(const SbName &name)**\
 **static int**	**getByName(const SbName &name, SoNodeList &list)**

Methods from class SoFieldContainer:

**void**	**setToDefaults()**\
 **SbBool**	**hasDefaultValues() const**\
 **SbBool**	**fieldsAreEqual(const SoFieldContainer \*fc) const**\
 **void**	**copyFieldValues(const SoFieldContainer \*fc, SbBool copyConnections = FALSE)**\
 **SbBool**	**set(const char \*fieldDataString)**\
 **void**	**get(SbString &fieldDataString)**\
 **virtual int**	**getFields(SoFieldList &resultList) const**\
 **virtual SoField \***	**getField(const SbName &fieldName) const**\
 **SbBool**	**getFieldName(const SoField \*field, SbName &fieldName) const**\
 **SbBool**	**isNotifyEnabled() const**\
 **SbBool**	**enableNotify(SbBool flag)**

Methods from class SoBase:

**void**	**ref()**\
 **void**	**unref() const**\
 **void**	**unrefNoDelete() const**\
 **void**	**touch()**\
 **virtual SoType**	**getTypeId() const**\
 **SbBool**	**isOfType(SoType type) const**\
 **virtual void**	**setName(const SbName &name)**\
 **virtual SbName**	**getName() const**

## DESCRIPTION

**SoEventCallback** will invoke application supplied callback functions during **SoHandleEventAction** traversal. Methods allow the application to specify which Inventor events should trigger callbacks, and which path must be picked, if any, for the callback invocation to occur. The application callback is able to get information about the event and the pick detail, and may grab events, release events, and set whether the event was handled.

If you register more than one callback function in an **SoEventCallback** node, all the callback functions will be invoked when an event occurs, even if one of the callbacks handles the event. However, if the event is handled by any of the callback functions, no other node in the scene graph will see the event.

## METHODS

**static SoType**	**getClassTypeId()**\
 Return the type id for the **SoEventCallback** class.

	**SoEventCallback()**\
 Constructor creates an event callback node with no event interest and a NULL path.

**void**	**setPath(SoPath \*path)**\
 **const SoPath \***	**getPath()**\
 Set and get the path which must be picked in order for the callbacks to be invoked. If the path is NULL, the callbacks will be invoked for every interesting event, as specified by **addEventCallback()**,  regardless of what is picked. The **setPath()** method makes its own copy of the passed path.

**void**	**addEventCallback(SoType eventType, SoEventCallbackCB \*f, void \*userData = NULL)**\
 **void**	**removeEventCallback(SoType eventType, SoEventCallbackCB \*f, void \*userData = NULL)**\
 Specifies the callback functions to be invoked for different event types. When invoked, the callback function will be passed the **userData**, along with a pointer to this **SoEventCallback** node. For example, passing **SoMouseButtonEvent::getClassTypeId()**  means callbacks will be invoked only when a mouse button is pressed or released. Passing **SoEvent::getClassTypeId()** for the **eventType** will cause the callback to be invoked for every event which passes through this event callback node.

**SoHandleEventAction \***	**getAction() const**\
 Returns the **SoHandleEventAction** currently traversing this node, or NULL if traversal is not taking place. This should be called only from callback functions.

**const SoEvent \***	**getEvent() const**\
 Returns the event currently being handled, or NULL if traversal is not taking place. This should be called only from callback functions.

**const SoPickedPoint \***	**getPickedPoint() const**\
 Returns pick information during **SoHandleEventAction** traversal, or NULL if traversal is not taking place. This should be called only from callback functions.

**void**	**setHandled()**\
 Tells the node the event was handled. The callback function is responsible for setting whether the event was handled or not. If there is more than one callback function registered with an **SoEventCallback** node, all of them will be invoked, regardless of whether one has handled the event or not. This should be called only from callback functions.

**SbBool**	**isHandled() const**\
 Returns whether the event has been handled. This should be called only from callback functions.

**void**	**grabEvents()**\
 **void**	**releaseEvents()**\
 Tells the event callback node to grab events or release the grab. While grabbing, the node will consume all events; however, each callback function will only be invoked for events of interest.

## FILE FORMAT/DEFAULTS

```
EventCallback {
}
```

## SEE ALSO

**SoInteraction, SoSelection, SoHandleEventAction, SoDragger**