# SetChainedPanelCallbackData

int SetChainedPanelCallbackData (int panel, const char typeName[], void *callbackData);

## Purpose

This function changes the callback data for a callback function that was linked to a panel by the ChainPanelCallback function.

## Parameters

Input
Name | Type | Description
panel | integer | The specifier for a particular panel that is currently in memory. This handle will have been returned by the LoadPanel, NewPanel, or DuplicatePanel function.
typeName | const char [] | Pass in the string that was passed to ChainPanelCallback to specify the type name of the link. If the control has not been previously linked by ChainPanelCallback with specified type name, then nothing is done and the error code UIEInvalidControlType (–45) is returned.
callbackData | void * | Pass a value of type pointer to void (void *). The callback data that was specified in the call to ChainPanelCallback will be replaced with this value.

## Return Value

Name | Type | Description
status | integer | Returns 0 if the function succeeded or a negative error code if the function failed. If the control has not been previously linked by ChainPanelCallback with specified type name, then nothing is done and the error code UIEInvalidControlType (–45) is returned. The possible negative error codes are:
–1 to –999 | A User Interface Library error code. (Constants are available in userint.h.)
A description of any of these error codes can be obtained using the GetGeneralErrorString function in the toolbox.fp instrument driver.