# CFReadStreamCreateForStreamedHTTPRequest(_:_:_:) Creates a read stream for a CFHTTP request message object whose body is too long to keep in memory. ``` func CFReadStreamCreateForStreamedHTTPRequest(_ alloc: CFAllocator?, _ requestHeaders: CFHTTPMessage, _ requestBody: CFReadStream) -> Unmanaged ``` ## Parameters `alloc` The allocator to use to allocate memory for the new object. Pass `NULL` or kCFAllocatorDefault to use the current default allocator. `requestHeaders` A CFHTTP request header. `requestBody` Read stream reference for the request body. ## Return Value A new read stream, or `NULL` if there was a problem creating the object. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). ## Discussion This function creates a read stream for the response to the `requestHeaders` plus `requestBody`. Call this function instead of [`CFReadStreamCreateForHTTPRequest(_:_:)`](/documentation/CFNetwork/CFReadStreamCreateForHTTPRequest(_:_:)) when the body of the request is so long that you do not want it to be resident in memory. Because streams cannot be reset, read streams created this way cannot be enabled for autoredirection. If the Content-Length header is set in `requestHeaders`, it is assumed that the length is correct and that `requestBody` will report end-of-stream after precisely Content-Length bytes have been read from it. If the Content-Length header is not set, the chunked transfer-encoding will be added to `requestHeaders`, and bytes read from `requestBody` will be transmitted chunked. The body of `requestHeaders` is ignored. After creating the read stream, you can call at any time to check the status of the stream. You may want to call `CFHTTPReadStreamSetProxy` to set the name and port number for a proxy. To serialize the request and send it, call . --- 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)