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

Library

libcrypto.lib

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);

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() or, for SSL applications, SSL_load_error_strings() first. If there is no text string registered for the given error code, the error string will contain the numeric code.

ERR_print_errors() 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.

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