BIO_GET_EX_NEW_INDEX(3)

💅 application-specific data: the BIO_get_ex_new_index(3) page 💅

Okay bestie, welcome to the Library Functions Manual page for BIO_GET_EX_NEW_INDEX(3) from libcrypto. Yes, the whole squad is here: we're talking about hanging your own application-specific data off OpenSSL data structures, and this page is the group chat for all the TYPE_* variants. 🫶

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✨ NAME ✨

The besties on this page are:

• BIO_get_ex_new_index
• BIO_set_ex_data
• BIO_get_ex_data
• BIO_set_app_data
• BIO_get_app_data
• UI_get_ex_new_index
• UI_set_ex_data
• UI_get_ex_data
• X509_get_ex_new_index
• X509_set_ex_data
• X509_get_ex_data
• EC_KEY_get_ex_new_index
• EC_KEY_get_ex_data
• EC_KEY_set_ex_data

...and their whole thing is application-specific data. Periodt. 💅

🌸 SYNOPSIS 🌸

This is the libcrypto situation, so grab these headers:

#include <openssl/bio.h>
#include <openssl/ui.h>
#include <openssl/x509.h>
#include <openssl/ec.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);

int
TYPE_set_app_data(TYPE *d, void *arg);

void *
TYPE_get_app_data(TYPE *d);

💖 DESCRIPTION 💖

In this description, TYPE is used as a placeholder for any of the OpenSSL datatypes listed in CRYPTO_get_ex_new_index(3). It's giving "one template to rule them all," and honestly? Slay.

These functions handle application-specific data in OpenSSL data structures. Their usage is identical to that of RSA_get_ex_new_index(3), RSA_set_ex_data(3), and RSA_get_ex_data(3). No new lore, same vibe. ✨

Here's the breakdown, bestie:

• TYPE_get_ex_new_index() is a macro that calls CRYPTO_get_ex_new_index(3) with the correct index value.
• TYPE_set_ex_data() is a function that calls CRYPTO_set_ex_data(3) with an offset into the opaque ex_data part of the TYPE object.
• TYPE_get_ex_data() is a function that calls CRYPTO_get_ex_data(3) with an offset into the opaque ex_data part of the TYPE object.

Heads up: TYPE_set_app_data() and TYPE_get_app_data() are deprecated wrapper macros that call TYPE_set_ex_data() and TYPE_get_ex_data() with idx set to 0. Deprecated means deprecated — don't pretend you didn't see this. 🫶

🫶 RETURN VALUES 🫶

• TYPE_get_new_ex_index() returns a new index on success or -1 on error. (Yes, that's the exact spelling in this section — I'm not out here correcting the page.)
• TYPE_set_ex_data() and TYPE_set_app_data() return 1 on success or 0 on error.
• TYPE_get_ex_data() and TYPE_get_app_data() return the application data or NULL if an error occurred.

👑 SEE ALSO 👑

Go read these next, iykyk:

• BIO_new(3)
• CRYPTO_get_ex_new_index(3)
• RSA_get_ex_new_index(3)
• X509_new(3)

🌈 HISTORY 🌈

The lore is lore-ing:

• BIO_set_app_data() and BIO_get_app_data() first appeared in SSLeay 0.8.1. BIO_get_ex_new_index(), BIO_set_ex_data(), and BIO_get_ex_data() first appeared in SSLeay 0.9.0. These functions have been available since OpenBSD 2.4.
• X509_get_ex_new_index(), X509_set_ex_data(), and X509_get_ex_data() first appeared in OpenSSL 0.9.5 and have been available since OpenBSD 2.7.
• UI_get_ex_new_index(), UI_set_ex_data(), and UI_get_ex_data() first appeared in OpenSSL 0.9.7 and have been available since OpenBSD 3.2.
• EC_KEY_get_ex_new_index(), EC_KEY_set_ex_data(), and EC_KEY_get_ex_data() first appeared in OpenSSL 1.1.0 and have been available since OpenBSD 6.5.

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💖 Cute little sign-off: this footer says Debian, June 8, 2025, and BIO_GET_EX_NEW_INDEX(3) — mwah, bye bestie! 🎀✨