Typedefs
typedef struct MDBX_cursor	MDBX_cursor
	Opaque structure for navigating through a table.

Enumerations
enum	MDBX_cursor_op { MDBX_FIRST , MDBX_FIRST_DUP , MDBX_GET_BOTH , MDBX_GET_BOTH_RANGE , MDBX_GET_CURRENT , MDBX_GET_MULTIPLE , MDBX_LAST , MDBX_LAST_DUP , MDBX_NEXT , MDBX_NEXT_DUP , MDBX_NEXT_MULTIPLE , MDBX_NEXT_NODUP , MDBX_PREV , MDBX_PREV_DUP , MDBX_PREV_NODUP , MDBX_SET , MDBX_SET_KEY , MDBX_SET_RANGE , MDBX_PREV_MULTIPLE , MDBX_SET_LOWERBOUND , MDBX_SET_UPPERBOUND , MDBX_TO_KEY_LESSER_THAN , MDBX_TO_KEY_LESSER_OR_EQUAL , MDBX_TO_KEY_EQUAL , MDBX_TO_KEY_GREATER_OR_EQUAL , MDBX_TO_KEY_GREATER_THAN , MDBX_TO_EXACT_KEY_VALUE_LESSER_THAN , MDBX_TO_EXACT_KEY_VALUE_LESSER_OR_EQUAL , MDBX_TO_EXACT_KEY_VALUE_EQUAL , MDBX_TO_EXACT_KEY_VALUE_GREATER_OR_EQUAL , MDBX_TO_EXACT_KEY_VALUE_GREATER_THAN , MDBX_TO_PAIR_LESSER_THAN , MDBX_TO_PAIR_LESSER_OR_EQUAL , MDBX_TO_PAIR_EQUAL , MDBX_TO_PAIR_GREATER_OR_EQUAL , MDBX_TO_PAIR_GREATER_THAN , MDBX_SEEK_AND_GET_MULTIPLE }
	Cursor operationsThis is the set of all operations for retrieving data using a cursor. More...

Functions
LIBMDBX_API MDBX_cursor *	mdbx_cursor_create (void *context)
	Create a cursor handle but not bind it to transaction nor DBI-handle.

LIBMDBX_API int	mdbx_cursor_set_userctx (MDBX_cursor cursor, void ctx)
	Set application information associated with the cursor.

LIBMDBX_API void *	mdbx_cursor_get_userctx (const MDBX_cursor *cursor)
	Get the application information associated with the MDBX_cursor.

LIBMDBX_API int	mdbx_cursor_bind (MDBX_txn txn, MDBX_cursor cursor, MDBX_dbi dbi)
	Bind cursor to specified transaction and DBI-handle.

LIBMDBX_API int	mdbx_cursor_unbind (MDBX_cursor *cursor)
	Unbind cursor from a transaction.

LIBMDBX_API int	mdbx_cursor_reset (MDBX_cursor *cursor)
	Сбрасывает состояние курсора.

LIBMDBX_API int	mdbx_cursor_open (MDBX_txn txn, MDBX_dbi dbi, MDBX_cursor *cursor)
	Create a cursor handle for the specified transaction and DBI handle.

LIBMDBX_API void	mdbx_cursor_close (MDBX_cursor *cursor)
	Closes a cursor handle without returning error code.

LIBMDBX_API int	mdbx_cursor_close2 (MDBX_cursor *cursor)
	Closes a cursor handle with returning error code.

LIBMDBX_API int	mdbx_txn_release_all_cursors_ex (const MDBX_txn txn, bool unbind, size_t count)
	Unbind or closes all cursors of a given transaction and of all its parent transactions if ones are.

int	mdbx_txn_release_all_cursors (const MDBX_txn *txn, bool unbind)
	Unbind or closes all cursors of a given transaction and of all its parent transactions if ones are.

LIBMDBX_API int	mdbx_cursor_renew (MDBX_txn txn, MDBX_cursor cursor)
	Renew a cursor handle for use within the given transaction.

LIBMDBX_API MDBX_txn *	mdbx_cursor_txn (const MDBX_cursor *cursor)
	Return the cursor's transaction handle.

LIBMDBX_API MDBX_dbi	mdbx_cursor_dbi (const MDBX_cursor *cursor)
	Return the cursor's table handle.

LIBMDBX_API int	mdbx_cursor_copy (const MDBX_cursor src, MDBX_cursor dest)
	Copy cursor position and state.

LIBMDBX_API int	mdbx_cursor_compare (const MDBX_cursor left, const MDBX_cursor right, bool ignore_multival)
	Сравнивает позицию курсоров.

LIBMDBX_API int	mdbx_cursor_eof (const MDBX_cursor *cursor)
	Determines whether the cursor is pointed to a key-value pair or not, i.e. was not positioned or points to the end of data.

LIBMDBX_API int	mdbx_cursor_on_first (const MDBX_cursor *cursor)
	Determines whether the cursor is pointed to the first key-value pair or not.

LIBMDBX_API int	mdbx_cursor_on_first_dup (const MDBX_cursor *cursor)
	Определяет стоит ли курсор на первом или единственном мульти-значении соответствующем ключу.

LIBMDBX_API int	mdbx_cursor_on_last (const MDBX_cursor *cursor)
	Determines whether the cursor is pointed to the last key-value pair or not.

LIBMDBX_API int	mdbx_cursor_on_last_dup (const MDBX_cursor *cursor)
	Определяет стоит ли курсор на последнем или единственном мульти-значении соответствующем ключу.

Detailed Description

Typedef Documentation

◆ MDBX_cursor

typedef struct MDBX_cursor MDBX_cursor

Opaque structure for navigating through a table.

See also: mdbx_cursor_create(); mdbx_cursor_bind(); mdbx_cursor_close()

Enumeration Type Documentation

◆ MDBX_cursor_op

enum MDBX_cursor_op

Cursor operationsThis is the set of all operations for retrieving data using a cursor.

See also: mdbx_cursor_get()

Enumerator
MDBX_FIRST	Position at first key/data item
MDBX_FIRST_DUP	MDBX_DUPSORT -only: Position at first data item of current key.
MDBX_GET_BOTH	MDBX_DUPSORT -only: Position at key/data pair.
MDBX_GET_BOTH_RANGE	MDBX_DUPSORT -only: Position at given key and at first data greater than or equal to specified data.
MDBX_GET_CURRENT	Return key/data at current cursor position
MDBX_GET_MULTIPLE	MDBX_DUPFIXED -only: Return up to a page of duplicate data items from current cursor position. Move cursor to prepare for MDBX_NEXT_MULTIPLE. See also MDBX_SEEK_AND_GET_MULTIPLE
MDBX_LAST	Position at last key/data item
MDBX_LAST_DUP	MDBX_DUPSORT -only: Position at last data item of current key.
MDBX_NEXT	Position at next data item
MDBX_NEXT_DUP	MDBX_DUPSORT -only: Position at next data item of current key.
MDBX_NEXT_MULTIPLE	MDBX_DUPFIXED -only: Return up to a page of duplicate data items from next cursor position. Move cursor to prepare for `MDBX_NEXT_MULTIPLE`. See also MDBX_SEEK_AND_GET_MULTIPLE MDBX_GET_MULTIPLE
MDBX_NEXT_NODUP	Position at first data item of next key
MDBX_PREV	Position at previous data item
MDBX_PREV_DUP	MDBX_DUPSORT -only: Position at previous data item of current key.
MDBX_PREV_NODUP	Position at last data item of previous key
MDBX_SET	Position at specified key
MDBX_SET_KEY	Position at specified key, return both key and data
MDBX_SET_RANGE	Position at first key greater than or equal to specified key.
MDBX_PREV_MULTIPLE	MDBX_DUPFIXED -only: Position at previous page and return up to a page of duplicate data items. See also MDBX_SEEK_AND_GET_MULTIPLE MDBX_GET_MULTIPLE
MDBX_SET_LOWERBOUND	Positions cursor at first key-value pair greater than or equal to specified, return both key and data, and the return code depends on whether a exact match. For non DUPSORT-ed collections this work the same to MDBX_SET_RANGE, but returns MDBX_SUCCESS if key found exactly or MDBX_RESULT_TRUE if greater key was found. For DUPSORT-ed a data value is taken into account for duplicates, i.e. for a pairs/tuples of a key and an each data value of duplicates. Returns MDBX_SUCCESS if key-value pair found exactly or MDBX_RESULT_TRUE if the next pair was returned.
MDBX_SET_UPPERBOUND	Positions cursor at first key-value pair greater than specified, return both key and data, and the return code depends on whether a upper-bound was found. For non DUPSORT-ed collections this work like MDBX_SET_RANGE, but returns MDBX_SUCCESS if the greater key was found or MDBX_NOTFOUND otherwise. For DUPSORT-ed a data value is taken into account for duplicates, i.e. for a pairs/tuples of a key and an each data value of duplicates. Returns MDBX_SUCCESS if the greater pair was returned or MDBX_NOTFOUND otherwise.
MDBX_TO_KEY_LESSER_THAN	Doubtless cursor positioning at a specified key.
MDBX_TO_KEY_LESSER_OR_EQUAL	Doubtless cursor positioning at a specified key.
MDBX_TO_KEY_EQUAL	Doubtless cursor positioning at a specified key.
MDBX_TO_KEY_GREATER_OR_EQUAL	Doubtless cursor positioning at a specified key.
MDBX_TO_KEY_GREATER_THAN	Doubtless cursor positioning at a specified key.
MDBX_TO_EXACT_KEY_VALUE_LESSER_THAN	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_EXACT_KEY_VALUE_LESSER_OR_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_EXACT_KEY_VALUE_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_EXACT_KEY_VALUE_GREATER_OR_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_EXACT_KEY_VALUE_GREATER_THAN	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_PAIR_LESSER_THAN	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_PAIR_LESSER_OR_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_PAIR_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_PAIR_GREATER_OR_EQUAL	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_TO_PAIR_GREATER_THAN	Doubtless cursor positioning at a specified key-value pair for dupsort/multi-value hives.
MDBX_SEEK_AND_GET_MULTIPLE	MDBX_DUPFIXED -only: Seek to given key and return up to a page of duplicate data items from current cursor position. Move cursor to prepare for MDBX_NEXT_MULTIPLE. See also MDBX_GET_MULTIPLE

Function Documentation

◆ mdbx_cursor_bind()

LIBMDBX_API int mdbx_cursor_bind	(	MDBX_txn *	txn,
		MDBX_cursor *	cursor,
		MDBX_dbi	dbi )

Bind cursor to specified transaction and DBI-handle.

Using of the mdbx_cursor_bind() is equivalent to calling mdbx_cursor_renew() but with specifying an arbitrary DBI-handle.

A cursor may be associated with a new transaction, and referencing a new or the same table handle as it was created with. This may be done whether the previous transaction is live or dead.

If the transaction is nested, then the cursor should not be used in its parent transaction. Otherwise it is no way to restore state if this nested transaction will be aborted, nor impossible to define the expected behavior.

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in]	txn	A transaction handle returned by mdbx_txn_begin().
[in]	dbi	A table handle returned by mdbx_dbi_open().
[in]	cursor	A cursor handle returned by mdbx_cursor_create().

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_EINVAL	An invalid parameter was specified.

◆ mdbx_cursor_close()

LIBMDBX_API void mdbx_cursor_close ( MDBX_cursor * cursor )

Closes a cursor handle without returning error code.

The cursor handle will be freed and must not be used again after this call, but its transaction may still be live.

This function returns void but panic in case of error. Use mdbx_cursor_close2() if you need to receive an error code instead of an app crash.

See also: mdbx_cursor_close2

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open() or mdbx_cursor_create().

◆ mdbx_cursor_close2()

LIBMDBX_API int mdbx_cursor_close2 ( MDBX_cursor * cursor )

Closes a cursor handle with returning error code.

The cursor handle will be freed and must not be used again after this call, but its transaction may still be live.

See also: mdbx_cursor_close

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open() or mdbx_cursor_create().

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_EINVAL	An invalid parameter was specified.

◆ mdbx_cursor_compare()

LIBMDBX_API int mdbx_cursor_compare	(	const MDBX_cursor *	left,
		const MDBX_cursor *	right,
		bool	ignore_multival )

Сравнивает позицию курсоров.

Функция предназначена для сравнения позиций двух инициализированных/установленных курсоров, связанных с одной транзакцией и одной таблицей (DBI-дескриптором). Если же курсоры связаны с разными транзакциями, либо с разными таблицами, либо один из них не инициализирован, то результат сравнения не определен (поведением может быть изменено в последующих версиях).

Parameters

[in]	left	Левый курсор для сравнения позиций.
[in]	right	Правый курсор для сравнения позиций.
[in]	ignore_multival	Булевой флаг, влияющий на результат только при сравнении курсоров для таблиц с мульти-значениями, т.е. с флагом MDBX_DUPSORT. В случае `true`, позиции курсоров сравниваются только по ключам, без учета позиционирования среди мульти-значений. Иначе, в случае `false`, при совпадении позиций по ключам, сравниваются также позиции по мульти-значениям.

Return values

Значение со знаком в семантике оператора <=> (меньше нуля, ноль, либо больше нуля) как результат сравнения позиций курсоров.

◆ mdbx_cursor_copy()

LIBMDBX_API int mdbx_cursor_copy	(	const MDBX_cursor *	src,
		MDBX_cursor *	dest )

Copy cursor position and state.

Parameters

[in]	src	A source cursor handle returned by mdbx_cursor_create() or mdbx_cursor_open().
[in,out]	dest	A destination cursor handle returned by mdbx_cursor_create() or mdbx_cursor_open().

Returns: A non-zero error value on failure and 0 on success.

◆ mdbx_cursor_create()

LIBMDBX_API MDBX_cursor * mdbx_cursor_create ( void * context )

Create a cursor handle but not bind it to transaction nor DBI-handle.

A cursor cannot be used when its table handle is closed. Nor when its transaction has ended, except with mdbx_cursor_bind() and mdbx_cursor_renew(). Also it can be discarded with mdbx_cursor_close().

A cursor must be closed explicitly always, before or after its transaction ends. It can be reused with mdbx_cursor_bind() or mdbx_cursor_renew() before finally closing it.

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in] context A pointer to application context to be associated with created cursor and could be retrieved by mdbx_cursor_get_userctx() until cursor closed.

Returns: Created cursor handle or NULL in case out of memory.

◆ mdbx_cursor_dbi()

LIBMDBX_API MDBX_dbi mdbx_cursor_dbi ( const MDBX_cursor * cursor )

Return the cursor's table handle.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

◆ mdbx_cursor_eof()

LIBMDBX_API int mdbx_cursor_eof ( const MDBX_cursor * cursor )

Determines whether the cursor is pointed to a key-value pair or not, i.e. was not positioned or points to the end of data.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

Returns: A MDBX_RESULT_TRUE or MDBX_RESULT_FALSE value, otherwise the error code.

Return values

MDBX_RESULT_TRUE	No more data available or cursor not positioned
MDBX_RESULT_FALSE	A data is available
Otherwise	the error code

◆ mdbx_cursor_get_userctx()

LIBMDBX_API void * mdbx_cursor_get_userctx ( const MDBX_cursor * cursor )

Get the application information associated with the MDBX_cursor.

See also: mdbx_cursor_set_userctx()

Parameters

[in] cursor An cursor handle returned by mdbx_cursor_create() or mdbx_cursor_open().

Returns: The pointer which was passed via the context parameter of mdbx_cursor_create() or set by mdbx_cursor_set_userctx(), or NULL if something wrong.

◆ mdbx_cursor_on_first()

LIBMDBX_API int mdbx_cursor_on_first ( const MDBX_cursor * cursor )

Determines whether the cursor is pointed to the first key-value pair or not.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

Returns: A MDBX_RESULT_TRUE or MDBX_RESULT_FALSE value, otherwise the error code.

Return values

MDBX_RESULT_TRUE	Cursor positioned to the first key-value pair
MDBX_RESULT_FALSE	Cursor NOT positioned to the first key-value pair
Otherwise	the error code

◆ mdbx_cursor_on_first_dup()

LIBMDBX_API int mdbx_cursor_on_first_dup ( const MDBX_cursor * cursor )

Определяет стоит ли курсор на первом или единственном мульти-значении соответствующем ключу.

Parameters

[in] cursor Курсор созданный посредством mdbx_cursor_open().

Returns: Значание MDBX_RESULT_TRUE, либо MDBX_RESULT_FALSE, иначе код ошибки.

Return values

MDBX_RESULT_TRUE	курсор установлен на первом или единственном мульти-значении соответствующем ключу.
MDBX_RESULT_FALSE	курсор НЕ установлен на первом или единственном мульти-значении соответствующем ключу.
ИНАЧЕ	код ошибки.

◆ mdbx_cursor_on_last()

LIBMDBX_API int mdbx_cursor_on_last ( const MDBX_cursor * cursor )

Determines whether the cursor is pointed to the last key-value pair or not.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

Returns: A MDBX_RESULT_TRUE or MDBX_RESULT_FALSE value, otherwise the error code.

Return values

MDBX_RESULT_TRUE	Cursor positioned to the last key-value pair
MDBX_RESULT_FALSE	Cursor NOT positioned to the last key-value pair
Otherwise	the error code

◆ mdbx_cursor_on_last_dup()

LIBMDBX_API int mdbx_cursor_on_last_dup ( const MDBX_cursor * cursor )

Определяет стоит ли курсор на последнем или единственном мульти-значении соответствующем ключу.

Parameters

[in] cursor Курсор созданный посредством mdbx_cursor_open().

Returns: Значание MDBX_RESULT_TRUE, либо MDBX_RESULT_FALSE, иначе код ошибки.

Return values

MDBX_RESULT_TRUE	курсор установлен на последнем или единственном мульти-значении соответствующем ключу.
MDBX_RESULT_FALSE	курсор НЕ установлен на последнем или единственном мульти-значении соответствующем ключу.
ИНАЧЕ	код ошибки.

◆ mdbx_cursor_open()

LIBMDBX_API int mdbx_cursor_open	(	MDBX_txn *	txn,
		MDBX_dbi	dbi,
		MDBX_cursor **	cursor )

Create a cursor handle for the specified transaction and DBI handle.

Using of the mdbx_cursor_open() is equivalent to calling mdbx_cursor_create() and then mdbx_cursor_bind() functions.

A cursor cannot be used when its table handle is closed. Nor when its transaction has ended, except with mdbx_cursor_bind() and mdbx_cursor_renew(). Also it can be discarded with mdbx_cursor_close().

A cursor must be closed explicitly always, before or after its transaction ends. It can be reused with mdbx_cursor_bind() or mdbx_cursor_renew() before finally closing it.

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in]	txn	A transaction handle returned by mdbx_txn_begin().
[in]	dbi	A table handle returned by mdbx_dbi_open().
[out]	cursor	Address where the new MDBX_cursor handle will be stored.

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_EINVAL	An invalid parameter was specified.

◆ mdbx_cursor_renew()

LIBMDBX_API int mdbx_cursor_renew	(	MDBX_txn *	txn,
		MDBX_cursor *	cursor )

Renew a cursor handle for use within the given transaction.

A cursor may be associated with a new transaction whether the previous transaction is running or finished.

Using of the mdbx_cursor_renew() is equivalent to calling mdbx_cursor_bind() with the DBI-handle that previously the cursor was used with.

Note: In contrast to LMDB, the MDBX allow any cursor to be re-used by using mdbx_cursor_renew(), to avoid unnecessary malloc/free overhead until it freed by mdbx_cursor_close().

Parameters

[in]	txn	A transaction handle returned by mdbx_txn_begin().
[in]	cursor	A cursor handle returned by mdbx_cursor_open().

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_EINVAL	An invalid parameter was specified.
MDBX_BAD_DBI	The cursor was not bound to a DBI-handle or such a handle became invalid.

◆ mdbx_cursor_reset()

LIBMDBX_API int mdbx_cursor_reset ( MDBX_cursor * cursor )

Сбрасывает состояние курсора.

В результате сброса курсор становится неустановленным и не позволяет выполнять операции относительного позиционирования, получения или изменения данных, до установки на позицию не зависящую от текущей. Что позволяет приложению пресекать дальнейшие операции без предварительного позиционирования курсора.

Parameters

[in] cursor Указатель на курсор.

Returns: Результат операции сканирования, либо код ошибки.

◆ mdbx_cursor_set_userctx()

LIBMDBX_API int mdbx_cursor_set_userctx	(	MDBX_cursor *	cursor,
		void *	ctx )

Set application information associated with the cursor.

See also: mdbx_cursor_get_userctx()

Parameters

[in]	cursor	An cursor handle returned by mdbx_cursor_create() or mdbx_cursor_open().
[in]	ctx	An arbitrary pointer for whatever the application needs.

Returns: A non-zero error value on failure and 0 on success.

◆ mdbx_cursor_txn()

LIBMDBX_API MDBX_txn * mdbx_cursor_txn ( const MDBX_cursor * cursor )

Return the cursor's transaction handle.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

◆ mdbx_cursor_unbind()

LIBMDBX_API int mdbx_cursor_unbind ( MDBX_cursor * cursor )

Unbind cursor from a transaction.

Unbinded cursor is disassociated with any transactions but still holds the original DBI-handle internally. Thus it could be renewed with any running transaction or closed.

If the transaction is nested, then the cursor should not be used in its parent transaction. Otherwise it is no way to restore state if this nested transaction will be aborted, nor impossible to define the expected behavior.

See also: mdbx_cursor_renew(); mdbx_cursor_bind(); mdbx_cursor_close(); mdbx_cursor_reset()

Note: In contrast to LMDB, the MDBX required that any opened cursors can be reused and must be freed explicitly, regardless ones was opened in a read-only or write transaction. The REASON for this is eliminates ambiguity which helps to avoid errors such as: use-after-free, double-free, i.e. memory corruption and segfaults.

Parameters

[in] cursor A cursor handle returned by mdbx_cursor_open().

Returns: A non-zero error value on failure and 0 on success.

◆ mdbx_txn_release_all_cursors()

int mdbx_txn_release_all_cursors	(	const MDBX_txn *	txn,
		bool	unbind )

inline

Unbind or closes all cursors of a given transaction and of all its parent transactions if ones are.

Unbinds either closes all cursors associated (opened, renewed or binded) with the given transaction in a bulk with minimal overhead.

See also: mdbx_cursor_unbind(); mdbx_cursor_close()

Parameters

[in]	txn	A transaction handle returned by mdbx_txn_begin().
[in]	unbind	If non-zero, unbinds cursors and leaves ones reusable. Otherwise close and dispose cursors.

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_BAD_TXN	Given transaction is invalid or has a child/nested transaction transaction.

◆ mdbx_txn_release_all_cursors_ex()

LIBMDBX_API int mdbx_txn_release_all_cursors_ex	(	const MDBX_txn *	txn,
		bool	unbind,
		size_t *	count )

Unbind or closes all cursors of a given transaction and of all its parent transactions if ones are.

Unbinds either closes all cursors associated (opened, renewed or binded) with the given transaction in a bulk with minimal overhead.

See also: mdbx_cursor_unbind(); mdbx_cursor_close()

Parameters

[in]	txn	A transaction handle returned by mdbx_txn_begin().
[in]	unbind	If non-zero, unbinds cursors and leaves ones reusable. Otherwise close and dispose cursors.
[in,out]	count	An optional pointer to return the number of cursors processed by the requested operation.

Returns: A non-zero error value on failure and 0 on success, some possible errors are:

Return values

MDBX_THREAD_MISMATCH	Given transaction is not owned by current thread.
MDBX_BAD_TXN	Given transaction is invalid or has a child/nested transaction transaction.

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ MDBX_cursor

Enumeration Type Documentation

◆ MDBX_cursor_op

Function Documentation

◆ mdbx_cursor_bind()

◆ mdbx_cursor_close()

◆ mdbx_cursor_close2()

◆ mdbx_cursor_compare()

◆ mdbx_cursor_copy()

◆ mdbx_cursor_create()

◆ mdbx_cursor_dbi()

◆ mdbx_cursor_eof()

◆ mdbx_cursor_get_userctx()

◆ mdbx_cursor_on_first()

◆ mdbx_cursor_on_first_dup()

◆ mdbx_cursor_on_last()

◆ mdbx_cursor_on_last_dup()

◆ mdbx_cursor_open()

◆ mdbx_cursor_renew()

◆ mdbx_cursor_reset()

◆ mdbx_cursor_set_userctx()

◆ mdbx_cursor_txn()

◆ mdbx_cursor_unbind()

◆ mdbx_txn_release_all_cursors()

◆ mdbx_txn_release_all_cursors_ex()