OPENSSL_USER_MACROS(7ssl)

📦 version 4.1.0, in nixos 26.05, nixpkgs unstable

💅 openssl_user_macros (7ssl) — the user defined macros page

okay bestie so this is OPENSSL_USER_MACROS(7ssl), one of the OpenSSL man pages, and it's genuinely the ✨meta✨ page — it's all about the macros you the programmer get to define yourself. no cap, it's giving "control panel for the headers" energy 🎛️

🌸 NAME 🌸

openssl_user_macros, OPENSSL_API_COMPAT, OPENSSL_ENGINE_STUBS, OPENSSL_NO_DEPRECATED, OPENSSL_SUPPRESS_DEPRECATED — User defined macros 🫶

✨ DESCRIPTION ✨

User defined macros let the programmer control certain aspects of what gets exposed by the OpenSSL headers. that's the whole vibe 🔥

NOTE: to be effective, a user defined macro must be defined before including any header file that depends on it — either in the compilation command (cc -DMACRO=value) or by defining the macro in source before including any headers. order matters, bestie, this is not a "define it later, it'll be fine" situation 😭

Other manual pages may refer to this page when declarations depend on user defined macros. so if you got sent here from somewhere else, hi, welcome, you're in the right place 🎀

👑 The macros 👑

💜 OPENSSL_API_COMPAT

The value is a version number, given in one of the following two forms:

"0xMNNFF000L"

This is the form supported for all versions up to 1.1.x, where M represents the major number, NN represents the minor number, and FF represents the fix number, as a hexadecimal number. For version 1.1.0, that's 0x10100000L.

Any version number may be given, but these numbers are the current known major deprecation points, making them the most meaningful:

  • 0x00908000L (version 0.9.8)
  • 0x10000000L (version 1.0.0)
  • 0x10100000L (version 1.1.0)

For convenience, higher numbers are accepted as well, as long as feasible. For example, 0x60000000L will work as expected. However, it is recommended to start using the second form instead 👇

"mmnnpp"

This form is a simple decimal number calculated with this formula:

major * 10000 + minor * 100 + patch

where major, minor and patch are the desired major, minor and patch components of the version number. For example:

30000 corresponds to version 3.0.0
10002 corresponds to version 1.0.2
420101 corresponds to version 42.1.1

If OPENSSL_API_COMPAT is undefined, this default value is used in its place: 40100 ⭐

🧚 OPENSSL_ENGINE_STUBS

ENGINE API, as defined in openssl/engine.h, was permanently removed in OpenSSL 4.0. 💀 like, gone gone.

The user application can use the define OPENSSL_ENGINE_STUBS to enable stub macros for API ENGINE functions. It should temporarily help to ease the transition of applications without source code modifications. it's basically a little floatie for your code while it learns to swim 🩱

Note that all stub macros emulate API function failures; they will not restore the removed API functionality even if the OPENSSL_API_COMPAT define is used. so like, don't expect the ghost of ENGINE to come back and actually work, it won't 🙈

🦋 OPENSSL_NO_DEPRECATED

If this macro is defined, all deprecated public symbols in all OpenSSL versions up to and including the version given by OPENSSL_API_COMPAT (or the default value given above, when OPENSSL_API_COMPAT isn't defined) will be hidden. poof, invisible 👻

🌈 OPENSSL_SUPPRESS_DEPRECATED

If this macro is defined, compiler warnings about usage of deprecated symbols are suppressed in the compilation unit. seems iconic right? but consider using OSSL_BEGIN_ALLOW_DEPRECATED(3) and OSSL_END_ALLOW_DEPRECATED(3) for localised deprecation warning suppression, however. the scoped version is the main character here, this one is the whole-unit blunt instrument 💅

🎀 SEE ALSO 🎀

Copyright 2018-2026 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>.

okay that's the whole page, you ate that 🍓 this was OpenSSL version 4.1.0, dated 2026-10-23 — mwah, go define some macros, bestie, you've got this 💜👑

📦 where this page comes from