mongocxx::v_noabi::read_concern Class Reference

#include <mongocxx/v_noabi/mongocxx/read_concern.hpp>

Description

Controls the consistency and isolation properties of data read from replica sets and sharded clusters.

Read concern can be set at the client, database, or collection level. The read concern can also be provided via connection string, and will be parsed and set on the client constructed for the URI.

See also

• Read Concern (MongoDB Manual)

Public Types
enum class	level
	A class to represent the read concern level for read operations. More...

Public Member Functions
	read_concern ()=default
	Constructs a new read_concern with default acknowledge_level of k_server_default.
	read_concern (v1::read_concern rc)
	Construct with the mongocxx::v1 equivalent.
level	acknowledge_level () const
	Gets the current read concern level.
void	acknowledge_level (level rc_level)
	Sets the read concern level.
bsoncxx::v1::stdx::string_view	acknowledge_string () const
	Gets the current read concern string.
void	acknowledge_string (bsoncxx::v1::stdx::string_view rc_string)
	Sets the read concern string. Any valid read concern string (e.g. "local", "majority", "linearizable", "") may be passed in. For forward-compatibility with read concern levels introduced in the future, no validation is performed on this string.
	operator v1::read_concern () &&
	Convert to the mongocxx::v1 equivalent.
	operator v1::read_concern () const &
	Convert to the mongocxx::v1 equivalent.
bsoncxx::v_noabi::document::value	to_document () const
	Gets the document form of this read_concern.

Related Symbols
(Note that these are not member symbols.)
bool	operator== (read_concern const &lhs, read_concern const &rhs)
	Compares two read_concern objects for (in)-equality.
bool	operator!= (read_concern const &lhs, read_concern const &rhs)
	Compares two read_concern objects for (in)-equality.

Member Enumeration Documentation

level

enum class mongocxx::v_noabi::read_concern::level

strong

A class to represent the read concern level for read operations.

See also

• Read Concern Levels (MongoDB Manual)
• Default MongoDB Read Concerns/Write Concerns (MongoDB Manual)

Enumerator
k_local	Represent read concern level "local".
k_majority	Represent read concern level "majority".
k_linearizable	Represent read concern level "linearizable".
k_server_default	Represent the server's default read concern level.
k_unknown	Represent an unknown read concern level.
k_available	Represent read concern level "available".
k_snapshot	Represent read concern level "snapshot".

Constructor & Destructor Documentation

read_concern() [1/2]

mongocxx::v_noabi::read_concern::read_concern ( )

default

Constructs a new read_concern with default acknowledge_level of k_server_default.

The k_server_default acknowledge level has an empty acknowledge_string. Queries that run with this read_concern will use the server's default read_concern instead of specifying one.

read_concern() [2/2]

mongocxx::v_noabi::read_concern::read_concern ( v1::read_concern rc )

inline

Construct with the mongocxx::v1 equivalent.

Member Function Documentation

acknowledge_level() [1/2]

level mongocxx::v_noabi::read_concern::acknowledge_level ( ) const

inline

Gets the current read concern level.

If this was set with acknowledge_string to anything other than "local", "majority", "linearizable", or an empty string, this will return k_unknown.

Returns

The read concern level.

acknowledge_level() [2/2]

void mongocxx::v_noabi::read_concern::acknowledge_level

(

level

rc_level

)

Sets the read concern level.

Parameters

rc_level

Either k_local, k_majority, k_linearizable, or k_server_default.

Exceptions

mongocxx::v_noabi::exception

if rc_level is not k_local, k_majority, k_linearizable, or k_server_default.

acknowledge_string() [1/2]

bsoncxx::v1::stdx::string_view mongocxx::v_noabi::read_concern::acknowledge_string ( ) const

inline

Gets the current read concern string.

If the read concern level was set with acknowledge_level, this will return either "local", "majority", "linearizable", or an empty string for k_server_default.

Returns

The read concern string.

acknowledge_string() [2/2]

void mongocxx::v_noabi::read_concern::acknowledge_string ( bsoncxx::v1::stdx::string_view rc_string )

inline

Sets the read concern string. Any valid read concern string (e.g. "local", "majority", "linearizable", "") may be passed in. For forward-compatibility with read concern levels introduced in the future, no validation is performed on this string.

Parameters

rc_string

The read concern string.

operator v1::read_concern() [1/2]

mongocxx::v_noabi::read_concern::operator v1::read_concern ( ) &&

inlineexplicit

Convert to the mongocxx::v1 equivalent.

Postconditions:

• *this is in an assign-or-destroy-only state.

Warning

Invalidates all associated views.

operator v1::read_concern() [2/2]

mongocxx::v_noabi::read_concern::operator v1::read_concern ( ) const &

inlineexplicit

Convert to the mongocxx::v1 equivalent.

to_document()

bsoncxx::v_noabi::document::value mongocxx::v_noabi::read_concern::to_document ( ) const

inline

Gets the document form of this read_concern.

Returns

Document representation of this read_concern.

Friends And Related Symbol Documentation

operator!=

bool operator!= ( read_concern const & lhs, read_concern const & rhs )

friend

Compares two read_concern objects for (in)-equality.

operator==

bool operator== ( read_concern const & lhs, read_concern const & rhs )

friend

Compares two read_concern objects for (in)-equality.

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The documentation for this class was generated from the following file:

• mongocxx/v_noabi/mongocxx/read_concern.hpp