---
name: "XtAddCallback"
section: "3x"
platform: "linux"
package: "libxt-dev"
version: "4.3.0.dfsg.1-14sarge7"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/XtAddCallback/3x"
---

# XtAddCallback(3x)

add and remove callback procedures

## NAME

XtAddCallback, XtAddCallbacks, XtRemoveCallback, XtRemoveCallbacks, XtRemoveAllCallbacks - add and remove callback procedures

## SYNTAX

void XtAddCallback(Widget *w*, String *callback\_name*, XtCallbackProc *callback*, XtPointer *client\_data*);

void XtAddCallbacks(Widget *w*, String *callback\_name*, XtCallbackList *callbacks*);

void XtRemoveCallback(Widget *w*, String *callback\_name*, XtCallbackProc *callback*, XtPointer *client\_data*);

void XtRemoveCallbacks(Widget *w*, String *callback\_name*, XtCallbackList *callbacks*);

void XtRemoveAllCallbacks(Widget *w*, String *callback\_name*,

## ARGUMENTS

- *callback*

  Specifies the callback procedure.

- *callbacks*

  Specifies the null-terminated list of callback procedures and corresponding client data.

- *callback\_name*

  Specifies the callback list to which the procedure is to be appended or deleted. or the client data to match on the registered callback procedures

- *client\_data*

  Specifies the argument that is to be passed to the specified procedure when it is invoked by XtCallbacks or NULL,.

- *w*

  Specifies the widget.

## DESCRIPTION

The *XtAddCallback* function adds the specified callback procedure to the specified widget's callback list.

The *XtAddCallbacks* add the specified list of callbacks to the specified widget's callback list.

The *XtRemoveCallback* function removes a callback only if both the procedure and the client data match.

The *XtRemoveCallbacks* function removes the specified callback procedures from the specified widget's callback list.

The *XtRemoveAllCallbacks* function removes all the callback procedures from the specified widget's callback list.

## SEE ALSO

XtCallCallbacks(3Xt)\
 *X Toolkit Intrinsics - C Language Interface*\
 *Xlib - C Language X Interface*