# SSLWrite(_:_:_:_:) Performs a typical application-level write operation. ``` func SSLWrite(_ context: SSLContext, _ data: UnsafeRawPointer?, _ dataLength: Int, _ processed: UnsafeMutablePointer) -> OSStatus ``` ## Parameters `context` An SSL session context reference. `data` A pointer to the buffer of data to write. `dataLength` The amount, in bytes, of data to write. `processed` On return, the length, in bytes, of the data actually written. ## Return Value A result code. See [Secure Transport Result Codes](/documentation/Security/secure-transport-result-codes). ## Discussion The [`SSLWrite(_:_:_:_:)`](/documentation/Security/SSLWrite(_:_:_:_:)) function might call the [`SSLWriteFunc`](/documentation/Security/SSLWriteFunc) function that you provide (see [`SSLSetIOFuncs(_:_:_:)`](/documentation/Security/SSLSetIOFuncs(_:_:_:))). Because you may configure the underlying connection to operate in a no-blocking manner, a write operation might return `errSSLWouldBlock`, indicating that less data than requested was actually transferred. In this case, you should repeat the call to [`SSLWrite(_:_:_:_:)`](/documentation/Security/SSLWrite(_:_:_:_:)) until some other result is returned. --- 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)