NAME

       ERR_error_string, ERR_error_string_n, ERR_lib_error_string, ERR_func_error_string,
       ERR_reason_error_string - obtain human-readable error message

SYNOPSIS

        #include <openssl/err.h>

        char *ERR_error_string(unsigned long e, char *buf);
        void ERR_error_string_n(unsigned long e, char *buf, size_t len);

        const char *ERR_lib_error_string(unsigned long e);
        const char *ERR_reason_error_string(unsigned long e);

       Deprecated in OpenSSL 3.0:

        const char *ERR_func_error_string(unsigned long e);

DESCRIPTION

       ERR_error_string() generates a human-readable string representing the error code e, and
       places it at buf. buf must be at least 256 bytes long. If buf is NULL, the error string is
       placed in a static buffer.  Note that this function is not thread-safe and does no checks
       on the size of the buffer; use ERR_error_string_n() instead.

       ERR_error_string_n() is a variant of ERR_error_string() that writes at most len characters
       (including the terminating 0) and truncates the string if necessary.  For
       ERR_error_string_n(), buf may not be NULL.

       The string will have the following format:

        error:[error code]:[library name]::[reason string]

       error code is an 8 digit hexadecimal number, library name and reason string are ASCII
       text.

       ERR_lib_error_string() and ERR_reason_error_string() return the library name and reason
       string respectively.

       If there is no text string registered for the given error code, the error string will
       contain the numeric code.

       ERR_print_errors(3) can be used to print all error codes currently in the queue.

RETURN VALUES

       ERR_error_string() returns a pointer to a static buffer containing the string if buf ==
       NULL, buf otherwise.

       ERR_lib_error_string() and ERR_reason_error_string() return the strings, and NULL if none
       is registered for the error code.

       ERR_func_error_string() returns NULL.

SEE ALSO

       ERR_get_error(3), ERR_print_errors(3)

HISTORY

       ERR_func_error_string() became deprecated in OpenSSL 3.0.

COPYRIGHT

       Copyright 2000-2017 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>.