ERR_get_error(3) | OpenSSL | ERR_get_error(3)

# NAME

ERR_get_error, ERR_peek_error, ERR_peek_last_error, ERR_get_error_line, ERR_peek_error_line, ERR_peek_last_error_line, ERR_peek_error_func, ERR_peek_last_error_func, ERR_peek_error_data, ERR_peek_last_error_data, ERR_get_error_all, ERR_peek_error_all, ERR_peek_last_error_all, ERR_get_error_line_data, ERR_peek_error_line_data, ERR_peek_last_error_line_data - obtain error code and data

# SYNOPSIS

     #include <openssl/err.h>
     unsigned long ERR_get_error(void);
     unsigned long ERR_peek_error(void);
     unsigned long ERR_peek_last_error(void);
     unsigned long ERR_peek_error_line(const char **file, int *line);
     unsigned long ERR_peek_last_error_line(const char **file, int *line);
     unsigned long ERR_peek_error_func(const char **func);
     unsigned long ERR_peek_last_error_func(const char **func);
     unsigned long ERR_peek_error_data(const char **data, int *flags);
     unsigned long ERR_peek_last_error_data(const char **data, int *flags);
     unsigned long ERR_get_error_all(const char **file, int *line,
                                     const char **func,
                                     const char **data, int *flags);
     unsigned long ERR_peek_error_all(const char **file, int *line,
                                      const char **func,
                                      const char **data, int *flags);
     unsigned long ERR_peek_last_error_all(const char **file, int *line,
                                           const char *func,
                                           const char **data, int *flags);

The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):

     unsigned long ERR_get_error_line(const char **file, int *line);
     unsigned long ERR_get_error_line_data(const char **file, int *line,
                                           const char **data, int *flags);
     unsigned long ERR_peek_error_line_data(const char **file, int *line,
                                            const char **data, int *flags);
     unsigned long ERR_peek_last_error_line_data(const char **file, int *line,
                                                 const char **data, int *flags);

# DESCRIPTION

ERR_get_error() returns the earliest error code from the thread's error queue and removes the entry. This function can be called repeatedly until there are no more error codes to return.

ERR_peek_error() returns the earliest error code from the thread's error queue without modifying it.

ERR_peek_last_error() returns the latest error code from the thread's error queue without modifying it.

See ERR_GET_LIB(3) for obtaining further specific information such as the reason of the error, and ERR_error_string(3) for human-readable error messages.

ERR_get_error_all() is the same as ERR_get_error(), but on success it additionally stores the filename, line number and function where the error occurred in *file, *line and *func, and also extra text and flags in *data, *flags. If any of those parameters are NULL, it will not be changed. An unset filename is indicated as "", i.e. an empty string. An unset line number is indicated as 0. An unset function name is indicated as "", i.e. an empty string.

A pointer returned this way by these functions and the ones below is valid until the respective entry is overwritten in the error queue.

ERR_peek_error_line() and ERR_peek_last_error_line() are the same as ERR_peek_error() and ERR_peek_last_error(), but on success they additionally store the filename and line number where the error occurred in *file and *line, as far as they are not NULL. An unset filename is indicated as "", i.e., an empty string. An unset line number is indicated as 0.

ERR_peek_error_func() and ERR_peek_last_error_func() are the same as ERR_peek_error() and ERR_peek_last_error(), but on success they additionally store the name of the function where the error occurred in *func, unless it is NULL. An unset function name is indicated as "".

ERR_peek_error_data() and ERR_peek_last_error_data() are the same as ERR_peek_error() and ERR_peek_last_error(), but on success they additionally store additional data and flags associated with the error code in *data and *flags, as far as they are not NULL. Unset data is indicated as "". In this case the value given for the flag is irrelevant (and equals 0). *data contains a string if *flags&ERR_TXT_STRING is true.

ERR_peek_error_all() and ERR_peek_last_error_all() are combinations of all of the above.

ERR_get_error_line(), ERR_get_error_line_data(), ERR_peek_error_line_data() and ERR_peek_last_error_line_data() are older variants of ERR_get_error_all(), ERR_peek_error_all() and ERR_peek_last_error_all(), and may give confusing results. They should no longer be used and are therefore deprecated.

An application MUST NOT free the *data pointer (or any other pointers returned by these functions) with OPENSSL_free() as freeing is handled automatically by the error library.

# RETURN VALUES

The error code, or 0 if there is no error in the queue.

# SEE ALSO

ERR_error_string(3), ERR_GET_LIB(3)

# HISTORY

ERR_peek_error_func(), ERR_peek_last_error_func(), ERR_peek_error_data(), ERR_peek_last_error_data(), ERR_peek_error_all() and ERR_peek_last_error_all() were added in OpenSSL 3.0.

ERR_get_error_line(), ERR_get_error_line_data(), ERR_peek_error_line_data() and ERR_peek_last_error_line_data() became deprecated in OpenSSL 3.0.

# COPYRIGHT

Copyright 2000-2022 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>.

2026-06-09 | 3.5.7