---
title: "append(buffer:allocator:flags:)"
framework: coremedia
role: symbol
role_heading: Instance Method
path: "coremedia/cmblockbuffer/append(buffer:allocator:flags:)-8fws8"
---

# append(buffer:allocator:flags:)

Adds a sliced memory block to a block buffer using a custom allocator.

## Declaration

```swift
func append(buffer: Slice<UnsafeMutableRawBufferPointer>, allocator: CFAllocator? = kCFAllocatorDefault, flags: CMBlockBuffer.Flags = []) throws
```

## Parameters

- `buffer`: A block of memory to hold buffered data.
- `allocator`: An allocator for the memory block.
- `flags`: Feature and control flags.

## See Also

### Modifying a Block Buffer

- [append(length:allocator:range:flags:)](coremedia/cmblockbuffer/append(length:allocator:range:flags:).md)
- [append(buffer:allocator:flags:)](coremedia/cmblockbuffer/append(buffer:allocator:flags:)-28keu.md)
- [append(length:allocator:deallocator:range:flags:)](coremedia/cmblockbuffer/append(length:allocator:deallocator:range:flags:).md)
- [append(buffer:deallocator:flags:)](coremedia/cmblockbuffer/append(buffer:deallocator:flags:)-3bfef.md)
- [append(buffer:deallocator:flags:)](coremedia/cmblockbuffer/append(buffer:deallocator:flags:)-1ibzz.md)
- [CMBlockBuffer.CustomBlockAllocator](coremedia/cmblockbuffer/customblockallocator.md)
- [CMBlockBuffer.CustomBlockDeallocator](coremedia/cmblockbuffer/customblockdeallocator.md)
- [append(bufferReference:flags:)](coremedia/cmblockbuffer/append(bufferreference:flags:).md)
- [assureBlockMemory()](coremedia/cmblockbuffer/assureblockmemory().md)
- [withUnsafeMutableBytes(atOffset:_:)](coremedia/cmblockbuffer/withunsafemutablebytes(atoffset:_:).md)