---
title: "SecTransformPushbackAttribute(_:_:_:)"
framework: security
role: symbol
role_heading: Function
path: "security/sectransformpushbackattribute(_:_:_:)"
---

# SecTransformPushbackAttribute(_:_:_:)

Pushes a single value back for a specific attribute.

## Declaration

```swift
func SecTransformPushbackAttribute(_ ref: SecTransformImplementationRef, _ attribute: SecTransformStringOrAttribute, _ value: CFTypeRef) -> CFTypeRef?
```

## Parameters

- `ref`: A doc://com.apple.security/documentation/Security/SecTransformImplementationRef that is bound to an instance of a custom transform.
- `attribute`: The name or the attribute handle of the attribute whose value is to be pushed back. When using a name, see doc://com.apple.security/documentation/Security/transform-attributes for a list of valid key names.
- `value`: The value being pushed back.

## Return Value

Return Value An error on failure, or NULL on success. In Objective-C, call the CFRelease function to free the error’s memory when you are done with it.

## Discussion

Discussion Calling this function stops the flow of data into the specified attribute until any attribute is changed for the transform instance bound to the ref parameter.