# man > OPENSSL_API_COMPAT(7ssl)

[_OPENSSL_USER_MACROS_(7SSL)](https://www.chedong.com/phpMan.php/man/OPENSSLUSERMACROS/7SSL/markdown)                      OpenSSL                     [_OPENSSL_USER_MACROS_(7SSL)](https://www.chedong.com/phpMan.php/man/OPENSSLUSERMACROS/7SSL/markdown)

## NAME
       openssl_user_macros, OPENSSL_API_COMPAT, OPENSSL_NO_DEPRECATED - User defined macros

## DESCRIPTION
       User defined macros allow the programmer to control certain aspects of what is exposed by the
       OpenSSL headers.

       **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.

       Other manual pages may refer to this page when declarations depend on user defined macros.

### 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: 30000

       **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.

## COPYRIGHT
       Copyright 2018-2021 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>>.

3.0.13                                       2026-07-29                    [_OPENSSL_USER_MACROS_(7SSL)](https://www.chedong.com/phpMan.php/man/OPENSSLUSERMACROS/7SSL/markdown)