=pod

=head1 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_get_error_line_data, ERR_peek_error_line_data,
ERR_peek_last_error_line_data - obtain error code and data

=head1 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_get_error_line(const char **file, int *line);
 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_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);

=head1 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 L<ERR_GET_LIB(3)> for obtaining information about
location and reason of the error, and
L<ERR_error_string(3)> for human-readable error
messages.

ERR_get_error_line(), ERR_peek_error_line() and
ERR_peek_last_error_line() are the same as the above, but they
additionally store the file name and line number where
the error occurred in *B<file> and *B<line>, unless these are B<NULL>.

ERR_get_error_line_data(), ERR_peek_error_line_data() and
ERR_peek_last_error_line_data() store additional data and flags
associated with the error code in *B<data>
and *B<flags>, unless these are B<NULL>. *B<data> contains a string
if *B<flags>&B<ERR_TXT_STRING> is true.

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

=head1 RETURN VALUES

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

=head1 SEE ALSO

L<ERR_error_string(3)>,
L<ERR_GET_LIB(3)>

=head1 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
L<https://www.openssl.org/source/license.html>.

=cut
