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ERR_error_string

Section: OpenSSL (3)
Updated: 2017-05-25
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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_func_error_string(unsigned long e);
 const char *ERR_reason_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 120 bytes long. If buf is NULL, the error string is placed in a static buffer. 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]:[function name]:[reason string]

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

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

The OpenSSL error strings should be loaded by calling ERR_load_crypto_strings(3) or, for SSL applications, SSL_load_error_strings(3) first. 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(), ERR_func_error_string() and ERR_reason_error_string() return the strings, and NULL if none is registered for the error code.

HISTORY

ERR_error_string() is available in all versions of SSLeay and OpenSSL. ERR_error_string_n() was added in OpenSSL 0.9.6.