BIO_get_ex_new_index, BIO_set_ex_data, BIO_get_ex_data,

 #include <openssl/x509.h>
 int TYPE_get_ex_new_index(long argl, void *argp,
                           CRYPTO_EX_new *new_func,
                           CRYPTO_EX_dup *dup_func,
                           CRYPTO_EX_free *free_func);
 int TYPE_set_ex_data(TYPE *d, int idx, void *arg);
 void *TYPE_get_ex_data(TYPE *d, int idx);

In the description here, TYPE is used a placeholder for any of the OpenSSL datatypes listed in CRYPTO_get_ex_new_index(3).

These functions handle application-specific data for OpenSSL data structures.

TYPE_get_new_ex_index() is a macro that calls CRYPTO_get_ex_new_index() with the correct index value.

TYPE_set_ex_data() is a function that calls CRYPTO_set_ex_data() with an offset into the opaque exdata part of the TYPE object.

TYPE_get_ex_data() is a function that calls CRYPTO_get_ex_data() with an offset into the opaque exdata part of the TYPE object.

TYPE_get_new_ex_index() returns a new index on success or -1 on error.

TYPE_set_ex_data() returns 1 on success or 0 on error.

TYPE_get_ex_data() returns the application data or NULL if an error occurred.

CRYPTO_get_ex_new_index(3).

Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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>.