---
title: libkern
framework: kernel
role: collectionGroup
role_heading: API Collection
path: kernel/libkern
---

# libkern

Access the runtime support and base classes of the kernel library.

## Topics

### Fundamentals

- [Data Types](kernel/libkern/data_types.md)
- [Atomic Operations](kernel/libkern/atomic_operations.md)
- [Byte Order Utilities](kernel/libkern/byte_order_utilities.md)

### Memory

- [OSMalloc](kernel/1398447-osmalloc.md)
- [OSMalloc_Tagalloc](kernel/1398437-osmalloc_tagalloc.md)
- [OSMalloc_Tagfree](kernel/1398439-osmalloc_tagfree.md)
- [OSMalloc_noblock](kernel/1398431-osmalloc_noblock.md)
- [OSMalloc_nowait](kernel/1398445-osmalloc_nowait.md)
- [OSFree](kernel/1398441-osfree.md)
- [bzero](kernel/1579350-bzero.md)
- [bzero_phys](kernel/1593364-bzero_phys.md)

### Compression

- [deflate](kernel/1546831-deflate.md)
- [deflateBound](kernel/1546926-deflatebound.md)
- [deflateCopy](kernel/1546888-deflatecopy.md)
- [deflateEnd](kernel/1546858-deflateend.md)
- [deflateInit2_](kernel/1546915-deflateinit2.md)
- [deflateInit_](kernel/1546868-deflateinit.md)
- [deflateParams](kernel/1546901-deflateparams.md)
- [deflatePrime](kernel/1546857-deflateprime.md)
- [deflateReset](kernel/1546922-deflatereset.md)
- [deflateSetDictionary](kernel/1546824-deflatesetdictionary.md)
- [deflateSetHeader](kernel/1546907-deflatesetheader.md)
- [deflateTune](kernel/1546910-deflatetune.md)
- [inflate](kernel/1546920-inflate.md)
- [inflateBack](kernel/1546870-inflateback.md)
- [inflateBackEnd](kernel/1546827-inflatebackend.md)
- [inflateBackInit_](kernel/1546837-inflatebackinit.md)
- [inflateCopy](kernel/1546896-inflatecopy.md)
- [inflateEnd](kernel/1546948-inflateend.md)
- [inflateGetHeader](kernel/1546846-inflategetheader.md)
- [inflateInit2_](kernel/1546903-inflateinit2.md)
- [inflateInit_](kernel/1546829-inflateinit.md)
- [inflatePrime](kernel/1546947-inflateprime.md)
- [inflateReset](kernel/1546911-inflatereset.md)
- [inflateSetDictionary](kernel/1546878-inflatesetdictionary.md)
- [inflateSync](kernel/1546882-inflatesync.md)
- [inflateSyncPoint](kernel/1546820-inflatesyncpoint.md)
- [compress](kernel/1546928-compress.md)
- [compress2](kernel/1546887-compress2.md)
- [compressBound](kernel/1546819-compressbound.md)
- [adler32](kernel/1546941-adler32.md)
- [adler32_combine](kernel/1546886-adler32_combine.md)

### Cryptography

- [MD5_CTX](kernel/md5_ctx.md)
- [MD5Final](kernel/1537348-md5final.md)
- [MD5Init](kernel/1537346-md5init.md)
- [MD5Update](kernel/1537352-md5update.md)

### Non Quad Routines

- [fls](kernel/2869617-fls.md)
- [flsll](kernel/2869614-flsll.md)
- [ffs](kernel/1441046-ffs.md)
- [ffsll](kernel/2869615-ffsll.md)

### copyio

- [copyin](kernel/1441036-copyin.md)
- [copyinstr](kernel/1441071-copyinstr.md)
- [copyout](kernel/1441088-copyout.md)
- [copyoutstr](kernel/1441047-copyoutstr.md)
- [copystr](kernel/1441079-copystr.md)

## See Also

### IOKit Drivers

- [IOKit Fundamentals](kernel/iokit_fundamentals.md)
- [Hardware Families](kernel/hardware_families.md)
- [Driver Support](kernel/driver_support.md)