# OSData A container for untyped data. ``` class OSData; ``` ## Overview OSData represents an array of bytes as a container object. OSData objects are mutable: You can add bytes to them and overwrite portions of the byte array. OSData provides no concurrency protection; it’s up to the usage context to provide any protection necessary. ## Topics ### Creating a Data Object [`static OSDataPtr withBytes(const void *bytes, size_t numBytes);`](/documentation/DriverKit/OSData/withBytes) Allocates an OSData object with a copy of bytes. [`static OSDataPtr withBytesNoCopy(void *bytes, size_t numBytes);`](/documentation/DriverKit/OSData/withBytesNoCopy) Allocates an OSData object with a copy of bytes. [`static OSDataPtr withCapacity(uint32_t capacity);`](/documentation/DriverKit/OSData/withCapacity) Allocates an OSData object with preallocated capacity. [`static OSDataPtr withData(const OSData *inData);`](/documentation/DriverKit/OSData/withData-9y3g) Allocates an OSData object with a copy of bytes from another OSData. [`static OSDataPtr withData(const OSData *inData, size_t start, size_t numBytes);`](/documentation/DriverKit/OSData/withData-4rd8n) Allocates an OSData object with a copy of bytes from a subset of another OSData. [`OSDataPtrOSDataCreate(const void *bytes, size_t length);`](/documentation/DriverKit/OSDataCreate) [`typedef OSData * OSDataPtr;`](/documentation/DriverKit/OSDataPtr) [`virtual void free();`](/documentation/DriverKit/OSData/free) ### Getting Bytes [`const void * getBytesNoCopy() const;`](/documentation/DriverKit/OSData/getBytesNoCopy-91vcg) Returns a pointer to the OSData object’s internal data buffer. [`const void * getBytesNoCopy(size_t start, size_t numBytes) const;`](/documentation/DriverKit/OSData/getBytesNoCopy-53puz) Returns a pointer to the OSData object’s internal data buffer. [`size_t OSDataGetBytes(OSDataPtr obj, void *buffer, size_t offset, size_t length);`](/documentation/DriverKit/OSDataGetBytes) [`const void *OSDataGetBytesPtr(OSDataPtr obj, size_t offset, size_t length);`](/documentation/DriverKit/OSDataGetBytesPtr) ### Appending Data to the Object [`bool appendBytes(const void *bytes, size_t numBytes);`](/documentation/DriverKit/OSData/appendBytes-lbqa) Appends a buffer of bytes to the OSData object’s internal data buffer. [`bool appendBytes(const OSData *aDataObj);`](/documentation/DriverKit/OSData/appendBytes-38hs5) Appends a buffer of bytes to the OSData object’s internal data buffer. [`bool appendBytes(const void *bytes, size_t numBytes);`](/documentation/DriverKit/OSData/appendBytes-lbqa) Appends a buffer of bytes to the OSData object’s internal data buffer. [`bool OSDataAppendBytes(OSDataPtr data, const void *bytes, size_t length);`](/documentation/DriverKit/OSDataAppendBytes) ### Inspecting a Data Object [`size_t getCapacity() const;`](/documentation/DriverKit/OSData/getCapacity) Returns length of preallocated capacity. [`size_t getLength() const;`](/documentation/DriverKit/OSData/getLength) Returns length of data present. [`size_t OSDataGetLength(OSDataPtr obj);`](/documentation/DriverKit/OSDataGetLength) ### Comparing Data Objects [`bool isEqualTo(const OSData *aDataObj) const;`](/documentation/DriverKit/OSData/isEqualTo-2kdml) Compares the data with an OSData [`virtual bool isEqualTo(const OSMetaClassBase *anObject) const;`](/documentation/DriverKit/OSData/isEqualTo-4xz0j) Compares the data with an OSObject [`bool isEqualTo(const OSString *aString) const;`](/documentation/DriverKit/OSData/isEqualTo-5ssf5) Compares the data with an OSString [`bool isEqualTo(const void *bytes, size_t numBytes) const;`](/documentation/DriverKit/OSData/isEqualTo-79gqy) Compares the data with a pointer to bytes ## Relationships ### Inherits From [`OSContainer`](/documentation/DriverKit/OSContainer) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)