SSL_ALLOC_BUFFERS(3ossl)

📦
version 15.1 · 3 versions
, in freebsd 15.1

💅 SSL_ALLOC_BUFFERS 💅

okay so this page is SSL_ALLOC_BUFFERS(3ossl) bestie — it lives in the 3ossl section of the manual and it's literally all about managing the read and write buffers on your SSL structure. deep breaths, it's a short one, we got this 🫶

✨ NAME ✨

SSL_free_buffers, SSL_alloc_buffers — manage SSL structure buffers 🎀

✨ SYNOPSIS ✨

#include <openssl/ssl.h>

int SSL_free_buffers(SSL *ssl);
int SSL_alloc_buffers(SSL *ssl);

like, that's it. two functions. two ints. one SSL * each. iconic minimalism fr 💅

✨ DESCRIPTION ✨

okay so SSL_free_buffers() frees the read and write buffers of the given *ssl. and SSL_alloc_buffers() allocates the read and write buffers of the given *ssl. that's the whole vibe — one yeets, one rebuilds 🌸

now the tea ☕: there's this mode called SSL_MODE_RELEASE_BUFFERS and what it does is release read or write buffers whenever the buffers have been drained. so it's automatic. these functions are the manual override of that whole situation — they let applications control when buffers get freed and allocated, on your schedule, not the library's. main character energy, you decide 🔥

and here's the part where you can relax: after freeing the buffers, the buffers are automatically reallocated upon a new read or write. so SSL_alloc_buffers() genuinely does not need to be called 😌 it exists as a lil pre-allocation flex — use it to make sure the buffers are preallocated. and that's useful for two (2) reasons, bestie:

  • to avoid allocation during data processing (no surprise mallocs mid-flight, we love a predictable timeline ✨)
  • or with CRYPTO_set_mem_functions() to control where and how buffers are allocated (you pick the memory location, you pick the method, you're basically the manager of the buffers 💅)
💀 QUIC girlies listen up: these functions are no-ops when used with QUIC SSL objects. for QUIC, SSL_free_buffers() always fails, and SSL_alloc_buffers() always succeeds. that's the whole rule, no cap.

✨ RETURN VALUES ✨

the following return values can occur 👇

  • 0 (Failure) — SSL_free_buffers() returns 0 when there is pending data to be read or written (so like… it's not gonna free buffers with unfinished business in them 🙈). SSL_alloc_buffers() returns 0 when there is an allocation failure 😭
  • 1 (Success) — SSL_free_buffers() returns 1 if the buffers have been freed. this value is also returned if the buffers had been freed before calling SSL_free_buffers() — so idempotent-ish, slay 🎀. SSL_alloc_buffers() returns 1 if the buffers have been allocated. this value is also returned if the buffers had been allocated before calling SSL_alloc_buffers(). same energy, symmetric, we love to see it ✨

✨ SEE ALSO ✨

go read these next, bestie, they're all connected:

Copyright 2017-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

🦋 and that's the page!! this one's from version 3.5.6, dated 2026-04-07, and the footer still says SSL_ALLOC_BUFFERS(3ossl) if anyone asks. go forth and manage your buffers responsibly, mwah 💖✨

📦 where this page comes from