SSL_GET_EXTMS_SUPPORT(3SSL)

✨ SSL_GET_EXTMS_SUPPORT 💖

okay bestie, welcome to the SSL_get_extms_support page in the OpenSSL manual, section 3SSL. it's giving "short and sweet and extremely niche" and honestly? we love that for us. sit down, grab a strawberry 🍓, let's talk about whether your session used an extended master secret.

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🌸 NAME 🌸

SSL_get_extms_support — extended master secret support, bestie. that's the whole vibe. one function, one question: did we use extended master secret or not?

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🎀 SYNOPSIS 🎀

#include <openssl/ssl.h>

int SSL_get_extms_support(SSL *ssl);

yes girl, that's it. one include, one call. hydration. 💧

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🦋 DESCRIPTION 🦋

so SSL_get_extms_support() tells you whether the current session used extended master secret. that's literally the whole job. it looks at the session and goes "yes we did" or "no we didn't" or "girl i literally cannot tell you right now, we're mid-handshake" 😭

fun lil detail no cap: this function is implemented as a macro. so don't be out here trying to take its address or whatever, it's a macro, it's built different.

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💅 RETURN VALUES 💅

• 1 — the current session did use extended master secret. slay. ✨
• 0 — it did not. okay. we move.
• -1 — a handshake is currently in progress, i.e. it is not possible to determine if extended master secret was used. like, bestie, the vibe check is still loading, come back later 🙈

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🔥 SEE ALSO 🔥

• ssl(7) — go read that too, iykyk

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👑 COPYRIGHT 👑

Copyright 2015-2016 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>.

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k bye bestie!! this was OpenSSL 4.0.3, dated 2026-09-29 — SSL_GET_EXTMS_SUPPORT(3SSL), out. 💖✨🫶