A subclass of Sys_var_have to return dynamic values. More...

#include <sys_vars.h>

Inheritance diagram for Sys_var_have_func:

Public Member Functions
	Sys_var_have_func (const char name_arg, const char comment, enum SHOW_COMP_OPTION(func)(THD ), const char *substitute=nullptr)
	Construct a new variable. More...

const uchar *	global_value_ptr (THD *thd, std::string_view) override

Public Member Functions inherited from Sys_var_have
	Sys_var_have (const char name_arg, const char comment, int flag_args, ptrdiff_t off, size_t size, CMD_LINE getopt, PolyLock lock=nullptr, enum binlog_status_enum binlog_status_arg=VARIABLE_NOT_IN_BINLOG, on_check_function on_check_func=nullptr, on_update_function on_update_func=nullptr, const char substitute=nullptr, int parse_flag=PARSE_NORMAL)

bool	do_check (THD , set_var ) override

bool	session_update (THD , set_var ) override

bool	global_update (THD , set_var ) override

void	session_save_default (THD , set_var ) override
	save the session default value of the variable in var More...

void	global_save_default (THD , set_var ) override
	save the global default value of the variable in var More...

void	saved_value_to_string (THD , set_var , char *) override
	This function converts value stored in save_result to string. More...

const uchar *	session_value_ptr (THD , THD , std::string_view) override
	A pointer to a value of the variable for SHOW. More...

bool	check_update_type (Item_result) override

Public Member Functions inherited from sys_var
	sys_var (sys_var_chain chain, const char name_arg, const char comment, int flag_args, ptrdiff_t off, int getopt_id, enum get_opt_arg_type getopt_arg_type, SHOW_TYPE show_val_type_arg, longlong def_val, PolyLock lock, enum binlog_status_enum binlog_status_arg, on_check_function on_check_func, on_update_function on_update_func, const char substitute, int parse_flag, sys_var persisted_alias=nullptr, bool is_persisted_deprecated=false)
	sys_var constructor More...

virtual	~sys_var ()=default

const char *	get_deprecation_substitute ()

virtual void	cleanup ()
	All the cleanup procedures should be performed here. More...

virtual sys_var_pluginvar *	cast_pluginvar ()
	downcast for sys_var_pluginvar. More...

bool	check (THD thd, set_var var)

const uchar *	value_ptr (THD running_thd, THD target_thd, enum_var_type type, std::string_view keycache_name)

const uchar *	value_ptr (THD *thd, enum_var_type type, std::string_view keycache_name)

virtual void	update_default (longlong new_def_value)

virtual longlong	get_default ()

virtual longlong	get_min_value ()

virtual ulonglong	get_max_value ()

virtual ulong	get_var_type ()
	Returns variable type. More...

virtual void	set_arg_source (get_opt_arg_source *)

virtual void	set_is_plugin (bool)

virtual enum_variable_source	get_source ()

virtual const char *	get_source_name ()

virtual void	set_source (enum_variable_source src)

virtual bool	set_source_name (const char *path)

virtual bool	set_user (const char *usr)

virtual const char *	get_user ()

virtual const char *	get_host ()

virtual bool	set_host (const char *hst)

virtual ulonglong	get_timestamp () const

virtual void	set_user_host (THD *thd)

my_option *	get_option ()

virtual void	set_timestamp ()

virtual void	set_timestamp (ulonglong ts)

virtual bool	is_non_persistent ()

bool	set_default (THD thd, set_var var)
	Update the system variable with the default value from either session or global scope. More...

bool	update (THD thd, set_var var)

SHOW_TYPE	show_type ()

int	scope () const

const CHARSET_INFO *	charset (THD *thd)

bool	is_readonly () const

bool	not_visible () const

bool	is_trilevel () const

bool	is_persist_readonly () const

bool	is_parse_early () const

bool	is_sensitive () const

bool	is_hint_updateable () const
	Check if the variable can be set using SET_VAR hint. More...

bool	is_struct ()
	the following is only true for keycache variables, that support the syntax @keycache_name.variable_name More...

bool	is_written_to_binlog (enum_var_type type)

bool	check_scope (enum_var_type query_type)
	Return true for success if: Global query and variable scope is GLOBAL or SESSION, or Session query and variable scope is SESSION or ONLY_SESSION. More...

bool	is_global_persist (enum_var_type type)

bool	is_settable_at_command_line ()
	Return true if settable at the command line. More...

bool	register_option (std::vector< my_option > *array, int parse_flags)

void	do_deprecated_warning (THD *thd)

Item *	copy_value (THD *thd)
	Create item from system variable value. More...

void	save_default (THD thd, set_var var)

bool	check_if_sensitive_in_context (THD *, bool suppress_errors=true) const

Protected Attributes
enum SHOW_COMP_OPTION(*	func_ )(THD *)

Protected Attributes inherited from sys_var
int	flags
	or'ed flag_enum values More...

int	m_parse_flag
	either PARSE_EARLY or PARSE_NORMAL. More...

const SHOW_TYPE	show_val_type
	what value_ptr() returns for sql_show.cc More...

my_option	option
	min, max, default values are stored here More...

PolyLock *	guard
	second lock that protects the variable More...

ptrdiff_t	offset
	offset to the value from global_system_variables More...

on_check_function	on_check

pre_update_function	pre_update
	Pointer to function to be invoked before updating system variable (but after calling on_check hook), while we do not hold any locks yet. More...

on_update_function	on_update

const char *const	deprecation_substitute

bool	is_os_charset
	true if the value is in character_set_filesystem More...

struct get_opt_arg_source	source

char	user [USERNAME_CHAR_LENGTH+1]

char	host [HOSTNAME_LENGTH+1]

ulonglong	timestamp

Static Protected Attributes
static enum SHOW_COMP_OPTION	dummy_

Additional Inherited Members
Public Types inherited from sys_var
enum	flag_enum { GLOBAL = 0x0001 , SESSION = 0x0002 , ONLY_SESSION = 0x0004 , SCOPE_MASK = 0x03FF , READONLY = 0x0400 , ALLOCATED = 0x0800 , INVISIBLE = 0x1000 , TRI_LEVEL = 0x2000 , NOTPERSIST = 0x4000 , HINT_UPDATEABLE = 0x8000 , PERSIST_AS_READ_ONLY = 0x10000 , SENSITIVE = 0x20000 }

enum	binlog_status_enum { VARIABLE_NOT_IN_BINLOG , SESSION_VARIABLE_IN_BINLOG }
	Enumeration type to indicate for a system variable whether it will be written to the binlog or not. More...

Public Attributes inherited from sys_var
sys_var *	next

LEX_CSTRING	name

sys_var *	m_persisted_alias
	If the variable has an alias in the persisted variables file, this should point to it. More...

bool	m_is_persisted_deprecated
	If m_persist_alias is set, and the current variable is deprecated and m_persist_alias is the recommended substitute, then this flag should be set to true. More...

enum sys_var::binlog_status_enum	binlog_status

Static Public Attributes inherited from sys_var
static const int	PARSE_EARLY = 1

static const int	PARSE_NORMAL = 2

Protected Types inherited from sys_var
typedef bool(*	on_check_function) (sys_var self, THD thd, set_var *var)

typedef bool(*	pre_update_function) (sys_var self, THD thd, set_var *var)

typedef bool(*	on_update_function) (sys_var self, THD thd, enum_var_type type)

Protected Member Functions inherited from sys_var
uchar *	session_var_ptr (THD *thd)
	A pointer to a storage area of the variable, to the raw data. More...

uchar *	global_var_ptr ()

Detailed Description

A subclass of Sys_var_have to return dynamic values.

All the usual restrictions for Sys_var_have apply. But instead of reading a global variable it calls a function to return the value.

Constructor & Destructor Documentation

◆ Sys_var_have_func()

Sys_var_have_func::Sys_var_have_func	(	const char *	name_arg,
		const char *	comment,
		enum SHOW_COMP_OPTION()(THD )	func,
		const char *	substitute = `nullptr`
	)

inline

Construct a new variable.

Parameters

name_arg	The name of the variable
comment	Explanation of what the variable does
func	The function to call when in need to read the global value
substitute	If the variable is deprecated what to use instead

Member Function Documentation

◆ global_value_ptr()

const uchar * Sys_var_have_func::global_value_ptr	(	THD *	thd,
		std::string_view
	)

inlineoverridevirtual

Reimplemented from Sys_var_have.

Member Data Documentation

◆ dummy_

enum SHOW_COMP_OPTION Sys_var_have_func::dummy_

staticprotected

◆ func_

enum SHOW_COMP_OPTION(* Sys_var_have_func::func_) (THD *)

protected

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

sql/sys_vars.h

Public Member Functions

Protected Attributes

Static Protected Attributes

Additional Inherited Members