ERR_LOAD_STRINGS(3ossl)

💅 ERR_LOAD_STRINGS — the 3ossl glow-up 🎀

okay bestie, so this is the OpenSSL corner where you get to teach the error-code machine your own library's little vocabulary. no cap, it's the "load arbitrary error strings" girlies: ERR_load_strings, ERR_PACK, and ERR_get_next_error_library. she's niche but she EATS. ✨

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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 💖

ERR_load_strings() registers error strings for library number lib. so like… you tell OpenSSL "hey, this pile of codes? mine. here's what they mean." iconic behavior honestly 🫶

str is an array of error string data, and she looks like this:

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

The error code is generated from the library number and a function and reason code, like so: error = ERR_PACK(lib, func, reason). and yes, ERR_PACK() is a macro — she's built different, literally 🔥

The last entry in the array is {0,0}. terminus. the end. the final girl. don't forget her or the whole thing gets weird 💀

ERR_get_next_error_library() can be used to assign library numbers to user libraries at run time. so if you're out here building your own library and you need a number that isn't already taken? this is the hand-out window, babes 💅

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⭐ RETURN VALUES ⭐

• ERR_load_strings() — returns 1 for success and 0 for failure. that's it, that's the whole vibe check 🌈
• ERR_PACK() — returns the error code. your freshly-wrapped little gift 🎁
• ERR_get_next_error_library() — returns zero on failure, otherwise a new library number. fingers crossed for not zero 🙈

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🦋 SEE ALSO 🦋

ERR_load_strings(3) — go read the main character's page too, iykyk 👑

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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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alright bestie, that's the whole page — this was ERR_LOAD_STRINGS(3ossl) from the 3.5.6 release, dated 2026-04-07, and she slayed every line of it. mwah 🍓💜🧚