# SetMsgCallbackAttribute

int SetMsgCallbackAttribute (int panelHandle, int messageNumber, int callbackAttribute, . . .);

## Purpose

This function sets an attribute of the callback mechanism linked to the specified message number and panel.

## Parameters

Input
Name | Type | Description
panelHandle | integer | The handle of the panel for which a message–callback is installed.
messageNumber | integer | The number of the message for whose callback mechanism you wish to set an attribute.
callbackAttribute | integer | The callback attribute value to set. In the function panel, when you click the control or press <Enter>, <Spacebar>, or <Ctrl-down arrow>, a dialog box appears containing a hierarchical list of the available attributes. Attributes whose values cannot be obtained are dimmed. Help text is shown for each attribute. To select an attribute, double-click it or select it and then press <Enter>. If the attribute shown in this ring control has named constants as valid values, you can open a list of them by moving to the Attribute Value control and pressing <Enter>. The Attribute Values dialog box displays the values and value help for the constants.
attributeValue | any type (passed by value) | The value of the specified callback attribute. If the attribute shown in this control has named constants as valid values, you can open a list of them by pressing <Enter>. The Attribute Values dialog box displays the values and value help for the constants.

## Return Value

Name | Type | Description
status | integer | The status code that the function returns. 0 indicates success. A negative value indicates an error. This function may return a Programmer's Toolbox or UI Library error code. Call GetGeneralErrorString to obtain a text description of the error.