ERR_load_strings, ERR_PACK, ERR_get_next_error_library - load arbitrary error strings

#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);

ERR_load_strings() registers error strings for library number lib.

str is an array of error string data:

typedef struct ERR_string_data_st
    unsigned long error;
    char *string;

The error code is generated from the library number and a function and reason code: error = ERR_PACK(lib, func, reason). ERR_PACK() is a macro.

The last entry in the array is {0,0}.

ERR_get_next_error_library() can be used to assign library numbers to user libraries at run time.

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.


Copyright 2000-2021 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

2023-09-20 3.1.3