---
title: CMBlockBufferFlags
framework: coremedia
role: symbol
role_heading: Type Alias
path: coremedia/cmblockbufferflags
---

# CMBlockBufferFlags

A type for flags that control behaviors and features of block buffer APIs.

## Declaration

```swift
typealias CMBlockBufferFlags = UInt32
```

## Topics

### Constants

- [kCMBlockBufferAssureMemoryNowFlag](coremedia/kcmblockbufferassurememorynowflag.md)
- [kCMBlockBufferAlwaysCopyDataFlag](coremedia/kcmblockbufferalwayscopydataflag.md)
- [kCMBlockBufferDontOptimizeDepthFlag](coremedia/kcmblockbufferdontoptimizedepthflag.md)
- [kCMBlockBufferPermitEmptyReferenceFlag](coremedia/kcmblockbufferpermitemptyreferenceflag.md)

## See Also

### Creating a Block Buffer

- [CMBlockBufferCreateEmpty(allocator:capacity:flags:blockBufferOut:)](coremedia/cmblockbuffercreateempty(allocator:capacity:flags:blockbufferout:).md)
- [CMBlockBufferCreateWithMemoryBlock(allocator:memoryBlock:blockLength:blockAllocator:customBlockSource:offsetToData:dataLength:flags:blockBufferOut:)](coremedia/cmblockbuffercreatewithmemoryblock(allocator:memoryblock:blocklength:blockallocator:customblocksource:offsettodata:datalength:flags:blockbufferout:).md)
- [CMBlockBufferCreateWithBufferReference(allocator:referenceBuffer:offsetToData:dataLength:flags:blockBufferOut:)](coremedia/cmblockbuffercreatewithbufferreference(allocator:referencebuffer:offsettodata:datalength:flags:blockbufferout:).md)
- [CMBlockBufferCreateContiguous(allocator:sourceBuffer:blockAllocator:customBlockSource:offsetToData:dataLength:flags:blockBufferOut:)](coremedia/cmblockbuffercreatecontiguous(allocator:sourcebuffer:blockallocator:customblocksource:offsettodata:datalength:flags:blockbufferout:).md)
- [Block Buffer Flags](coremedia/block-buffer-flags.md)
- [CMBlockBufferCustomBlockSource](coremedia/cmblockbuffercustomblocksource.md)
- [Custom Block Source Version](coremedia/custom-block-source-version.md)