ERR_LOAD_STRINGS(3SSL)

💖 ERR_LOAD_STRINGS(3SSL) — the OpenSSL page about loading your own lil error strings 💖

okay bestie, gather round 🫶 this is a page from the OpenSSL manual set (that 3SSL up in the corner is the section, iykyk), and it's all about the ✨error string✨ machinery: registering your own strings, packing an error code together, and getting yourself a fresh library number. it's giving "I made my own library and I want pretty error messages" energy and honestly? slay.

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✨ NAME ✨

ERR_load_strings, ERR_PACK, ERR_get_next_error_library — load arbitrary error strings 💅

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🌸 SYNOPSIS 🌸

#include <openssl/err.h>

int ERR_load_strings(int lib, ERR_STRING_DATA *str);

int ERR_get_next_error_library(void);

unsigned long ERR_PACK(int lib, int func, int reason);

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🦋 DESCRIPTION 🦋

so ERR_load_strings() registers error strings for the library number lib. that's literally it, that's the gig. 👑

str is an array of error string data, and it looks exactly like this, no cap:

typedef struct ERR_string_data_st
{
    unsigned long error;
    char *string;
} ERR_STRING_DATA;

the error code gets generated from the library number plus a function and a reason code, like so: error = ERR_PACK(lib, func, reason). and fun fact — ERR_PACK() is a macro, not a function. no ordinary little function could ever 💀

the last entry in the array is {0,0}. that's the "we're done here" marker, do not forget it bestie, she is load-bearing. 🎀

and ERR_get_next_error_library()? she's the one you call when you want to assign library numbers to user libraries at run time. main character energy for real. 🌈

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💅 RETURN VALUES 💅

• ERR_load_strings() returns 1 for success and 0 for failure 😭
• ERR_PACK() returns the error code ⭐
• ERR_get_next_error_library() returns zero on failure, otherwise a new library number 🔥

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👑 SEE ALSO 👑

• ERR_load_strings(3)

(yes bestie, it really does reference itself. iconic. we love a self-aware queen. 💖)

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🎀 COPYRIGHT 🎀

Copyright 2000-2018 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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and that's the whole page, bestie, we ate and left no crumbs 🍓✨ this was OpenSSL 4.0.3, dated 2026-09-29, and the manual it lives in is ERR_LOAD_STRINGS(3SSL). go forth and register those strings, ily 🫶💜