> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration.md). # Plugin Declaration Plugin API reference: Plugin Declaration. Generated from the MariaDB server headers by doxygen and moxygen. > [`Plugin API`](/docs/server/reference/plugins/api-plugin/plugin_api.md) How to declare a plugin to the server. Macros for beginning and ending plugin declarations. Between [maria\_declare\_plugin](#maria_declare_plugin) and [maria\_declare\_plugin\_end](#maria_declare_plugin_end) there should be a [st\_maria\_plugin](#st_maria_plugin) struct for each plugin to be declared. ## Groups | Name | Description | | -------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------- | | [`Plugin License`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_license.md) | The allowable licenses for plugins | | [`Plugin Maturity`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_maturity.md) | The allowable code maturity levels for plugins | | [`Plugin Status Variables`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_status_vars.md) | | | [`Plugin Flags`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_flags.md) | Constants for plugin flags. | | [`Plugin System Variables`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_sys_vars.md) | Declarations for server variables and command line options. | ## Classes | Name | Description | | ------------------------------------- | ---------------------------------------------------- | | [`st_mysql_plugin`](#st_mysql_plugin) | Plugin description structure. | | [`st_maria_plugin`](#st_maria_plugin) | MariaDB extension for plugins declaration structure. | ## Macros | Name | Description | | ------------------------------------------------------------------- | --------------------------------------------------- | | [`MYSQL_DLLEXPORT`](#mysql_dllexport) | Declaration macros for MySQL plugins. | | [`MYSQL_PLUGIN_EXPORT`](#mysql_plugin_export) | Implementation independent macro for MySQL plugins. | | [`MYSQL_PLUGIN_INTERFACE_VERSION`](#mysql_plugin_interface_version) | MySQL plugin interface version | | [`MARIA_PLUGIN_INTERFACE_VERSION`](#maria_plugin_interface_version) | MariaDB plugin interface version | | [`__MYSQL_DECLARE_PLUGIN`](#mysql_declare_plugin) | | | [`MARIA_DECLARE_PLUGIN__`](#maria_declare_plugin) | | | [`mysql_declare_plugin`](#mysql_declare_plugin) | | | [`maria_declare_plugin`](#maria_declare_plugin) | | | [`mysql_declare_plugin_end`](#mysql_declare_plugin_end) | | | [`maria_declare_plugin_end`](#maria_declare_plugin_end) | | *** ### MYSQL\_DLLEXPORT ```cpp #define MYSQL_DLLEXPORT ``` Defined in plugin.h:45 Declaration macros for MySQL plugins. On Windows, exports from DLL need to be declared Also, plugin needs to be declared as extern "C" because MSVC unlike other compilers, uses C++ mangling for variables not only for functions. *** ### MYSQL\_PLUGIN\_EXPORT ```cpp #define MYSQL_PLUGIN_EXPORT extern "C" MYSQL_DLLEXPORT ``` Defined in plugin.h:58 Implementation independent macro for MySQL plugins. *** ### MYSQL\_PLUGIN\_INTERFACE\_VERSION ```cpp #define MYSQL_PLUGIN_INTERFACE_VERSION 0x0105 ``` Defined in plugin.h:115 MySQL plugin interface version *** ### MARIA\_PLUGIN\_INTERFACE\_VERSION ```cpp #define MARIA_PLUGIN_INTERFACE_VERSION 0x0110 ``` Defined in plugin.h:118 MariaDB plugin interface version *** ### \_\_MYSQL\_DECLARE\_PLUGIN ```cpp #define __MYSQL_DECLARE_PLUGIN(NAME, VERSION, PSIZE, DECLS, NAME, VERSION, PSIZE, DECLS) MYSQL_PLUGIN_EXPORT int _mysql_plugin_interface_version_; \ int _mysql_plugin_interface_version_= MYSQL_PLUGIN_INTERFACE_VERSION; \ MYSQL_PLUGIN_EXPORT int _mysql_sizeof_struct_st_plugin_; \ int _mysql_sizeof_struct_st_plugin_= sizeof(struct st_mysql_plugin); \ MYSQL_PLUGIN_EXPORT struct st_mysql_plugin _mysql_plugin_declarations_[]; \ struct st_mysql_plugin _mysql_plugin_declarations_[]= { ``` Defined in plugin.h:207 *** ### MARIA\_DECLARE\_PLUGIN\_\_ ```cpp #define MARIA_DECLARE_PLUGIN__(NAME, VERSION, PSIZE, DECLS, NAME, VERSION, PSIZE, DECLS) MYSQL_PLUGIN_EXPORT int _maria_plugin_interface_version_; \ int _maria_plugin_interface_version_= MARIA_PLUGIN_INTERFACE_VERSION; \ MYSQL_PLUGIN_EXPORT int _maria_sizeof_struct_st_plugin_; \ int _maria_sizeof_struct_st_plugin_= sizeof(struct st_maria_plugin); \ MYSQL_PLUGIN_EXPORT struct st_maria_plugin _maria_plugin_declarations_[]; \ struct st_maria_plugin _maria_plugin_declarations_[]= { ``` Defined in plugin.h:215 *** ### mysql\_declare\_plugin ```cpp #define mysql_declare_plugin(NAME, NAME) __MYSQL_DECLARE_PLUGIN(NAME, \ builtin_ ## NAME ## _plugin_interface_version, \ builtin_ ## NAME ## _sizeof_struct_st_plugin, \ builtin_ ## NAME ## _plugin) ``` Defined in plugin.h:225 *** ### maria\_declare\_plugin ```cpp #define maria_declare_plugin(NAME, NAME) MARIA_DECLARE_PLUGIN__(NAME, \ builtin_maria_ ## NAME ## _plugin_interface_version, \ builtin_maria_ ## NAME ## _sizeof_struct_st_plugin, \ builtin_maria_ ## NAME ## _plugin) ``` Defined in plugin.h:231 *** ### mysql\_declare\_plugin\_end ```cpp #define mysql_declare_plugin_end ,{0,0,0,0,0,0,0,0,0,0,0,0,0}} ``` Defined in plugin.h:237 *** ### maria\_declare\_plugin\_end ```cpp #define maria_declare_plugin_end ,{0,0,0,0,0,0,0,0,0,0,0,0,0}} ``` Defined in plugin.h:238 ## Typedefs | Return | Name | Description | | -------- | ------------------------------- | -------------------------------- | | `void *` | [`MYSQL_PLUGIN`](#mysql_plugin) | Opaque type for a plugin handle. | *** ### MYSQL\_PLUGIN ```cpp using MYSQL_PLUGIN = void * ``` Defined in plugin.h:78 Opaque type for a plugin handle. ## Class Definitions ### st\_mysql\_plugin ```cpp #include ``` ```cpp struct st_mysql_plugin ``` Defined in plugin.h:715 Plugin description structure. #### Public Attributes | Return | Name | Description | | ------------------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `int` | [`type`](#type) |

the plugin type (a MYSQL\_XXX\_PLUGIN value)

| | `void *` | [`info`](#info) |

pointer to type-specific plugin descriptor

| | `const char *` | [`name`](#name) |

plugin name

| | `const char *` | [`author`](#author) |

plugin author (for I\_S.PLUGINS)

| | `const char *` | [`descr`](#descr) |

general descriptive text (for I\_S.PLUGINS)

| | `int` | [`license`](#license) |

the plugin license (PLUGIN\_LICENSE\_XXX)

| | `int(*` | [`init`](#init) | The function to invoke when plugin is loaded. Plugin initialisation done here should defer any ALTER TABLE queries to after the ddl recovery is done, in the signal\_ddl\_recovery\_done() callback called by ha\_signal\_ddl\_recovery\_done(). | | `int(*` | [`deinit`](#deinit) | the function to invoke when plugin is unloaded | | `unsigned int` | [`version`](#version) |

plugin version (for I\_S.PLUGINS)

| | struct [`st_mysql_show_var`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_status_vars.md#st_mysql_show_var) \* | [`status_vars`](#status_vars) | | | `struct st_mysql_sys_var **` | [`system_vars`](#system_vars) | | | `void *` | [`__reserved1`](#reserved1) |

reserved for dependency checking

| | `unsigned long` | [`flags`](#flags) | flags for plugin | *** #### type ```cpp int type ``` Defined in plugin.h:717 the plugin type (a MYSQL\_XXX\_PLUGIN value)
*** #### info ```cpp void * info ``` Defined in plugin.h:718 pointer to type-specific plugin descriptor
*** #### name ```cpp const char * name ``` Defined in plugin.h:719 plugin name
*** #### author ```cpp const char * author ``` Defined in plugin.h:720 plugin author (for I\_S.PLUGINS)
*** #### descr ```cpp const char * descr ``` Defined in plugin.h:721 general descriptive text (for I\_S.PLUGINS)
*** #### license ```cpp int license ``` Defined in plugin.h:722 the plugin license (PLUGIN\_LICENSE\_XXX)
*** #### init ```cpp int(* init)(void *) ``` Defined in plugin.h:729 The function to invoke when plugin is loaded. Plugin initialisation done here should defer any ALTER TABLE queries to after the ddl recovery is done, in the signal\_ddl\_recovery\_done() callback called by ha\_signal\_ddl\_recovery\_done(). *** #### deinit ```cpp int(* deinit)(void *) ``` Defined in plugin.h:730 the function to invoke when plugin is unloaded *** #### version ```cpp unsigned int version ``` Defined in plugin.h:731 plugin version (for I\_S.PLUGINS)
*** #### status\_vars ```cpp struct st_mysql_show_var * status_vars ``` Type: struct [`st_mysql_show_var`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_status_vars.md#st_mysql_show_var) \* Defined in plugin.h:732 *** #### system\_vars ```cpp struct st_mysql_sys_var ** system_vars ``` Defined in plugin.h:733 *** #### \_\_reserved1 ```cpp void * __reserved1 ``` Defined in plugin.h:734 reserved for dependency checking
*** #### flags ```cpp unsigned long flags ``` Defined in plugin.h:735 flags for plugin ### st\_maria\_plugin ```cpp #include ``` ```cpp struct st_maria_plugin ``` Defined in plugin.h:746 MariaDB extension for plugins declaration structure. It also copies current MySQL plugin fields to have more independency in plugins extension #### Public Attributes | Return | Name | Description | | ------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `int` | [`type`](#type-1) |

the plugin type (a MYSQL\_XXX\_PLUGIN value)

| | `void *` | [`info`](#info-1) |

pointer to type-specific plugin descriptor

| | `const char *` | [`name`](#name-1) |

plugin name

| | `const char *` | [`author`](#author-1) |

plugin author (for SHOW PLUGINS)

| | `const char *` | [`descr`](#descr-1) | general descriptive text (for SHOW PLUGINS ) | | `int` | [`license`](#license-1) |

the plugin license (PLUGIN\_LICENSE\_XXX)

| | `int(*` | [`init`](#init-1) | The function to invoke when plugin is loaded. Plugin initialisation done here should defer any ALTER TABLE queries to after the ddl recovery is done, in the signal\_ddl\_recovery\_done() callback called by ha\_signal\_ddl\_recovery\_done(). | | `int(*` | [`deinit`](#deinit-1) | the function to invoke when plugin is unloaded | | `unsigned int` | [`version`](#version-1) |

plugin version (for SHOW PLUGINS)

| | struct [`st_mysql_show_var`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_status_vars.md#st_mysql_show_var) \* | [`status_vars`](#status_vars-1) | | | `struct st_mysql_sys_var **` | [`system_vars`](#system_vars-1) | | | `const char *` | [`version_info`](#version_info) | plugin version string | | `unsigned int` | [`maturity`](#maturity) | MariaDB\_PLUGIN\_MATURITY\_XXX | *** #### type ```cpp int type ``` Defined in plugin.h:748 the plugin type (a MYSQL\_XXX\_PLUGIN value)
*** #### info ```cpp void * info ``` Defined in plugin.h:749 pointer to type-specific plugin descriptor
*** #### name ```cpp const char * name ``` Defined in plugin.h:750 plugin name
*** #### author ```cpp const char * author ``` Defined in plugin.h:751 plugin author (for SHOW PLUGINS)
*** #### descr ```cpp const char * descr ``` Defined in plugin.h:752 general descriptive text (for SHOW PLUGINS ) *** #### license ```cpp int license ``` Defined in plugin.h:753 the plugin license (PLUGIN\_LICENSE\_XXX)
*** #### init ```cpp int(* init)(void *) ``` Defined in plugin.h:760 The function to invoke when plugin is loaded. Plugin initialisation done here should defer any ALTER TABLE queries to after the ddl recovery is done, in the signal\_ddl\_recovery\_done() callback called by ha\_signal\_ddl\_recovery\_done(). *** #### deinit ```cpp int(* deinit)(void *) ``` Defined in plugin.h:761 the function to invoke when plugin is unloaded *** #### version ```cpp unsigned int version ``` Defined in plugin.h:762 plugin version (for SHOW PLUGINS)
*** #### status\_vars ```cpp struct st_mysql_show_var * status_vars ``` Type: struct [`st_mysql_show_var`](/docs/server/reference/plugins/api-plugin/plugin_api/plugin_declaration/plugin_status_vars.md#st_mysql_show_var) \* Defined in plugin.h:763 *** #### system\_vars ```cpp struct st_mysql_sys_var ** system_vars ``` Defined in plugin.h:764 *** #### version\_info ```cpp const char * version_info ``` Defined in plugin.h:765 plugin version string *** #### maturity ```cpp unsigned int maturity ``` Defined in plugin.h:766 MariaDB\_PLUGIN\_MATURITY\_XXX