MySQL :: MySQL 8.4 C API Developer Guide :: 9.2.4 mysql_load_plugin() (original) (raw)

9.2.4 mysql_load_plugin()

struct st_mysql_client_plugin *
mysql_load_plugin(MYSQL *mysql,
                  const char *name,
                  int type,
                  int argc,
                  ...)

Description

Loads a MySQL client plugin, specified by name and type. An error occurs if the type is invalid or the plugin cannot be loaded.

It is not possible to load multiple plugins of the same type. An error occurs if you try to load a plugin of a type already loaded.

Specify the arguments as follows:

• mysql: A pointer to aMYSQL structure. The plugin API does not require a connection to a MySQL server, but this structure must be properly initialized. The structure is used to obtain connection-related information.
• name: The name of the plugin to load.
• type: The type of plugin to load, or −1 to disable type checking. If type is not −1, only plugins matching the type are considered for loading.
• argc: The number of following arguments (0 if there are none). Interpretation of any following arguments depends on the plugin type.

Another way to cause plugins to be loaded is to set theLIBMYSQL_PLUGINS environment variable to a list of semicolon-separated plugin names. For example:

export LIBMYSQL_PLUGINS="myplugin1;myplugin2"

Plugins named by LIBMYSQL_PLUGINS are loaded when the client program callsmysql_library_init(). No error is reported if problems occur loading these plugins.

The LIBMYSQL_PLUGIN_DIR environment variable can be set to the path name of the directory in which to look for client plugins. This variable is used in two ways:

• During client plugin preloading, the value of the--plugin-dir option is not available, so client plugin loading fails unless the plugins are located in the hardwired default directory. If the plugins are located elsewhere,LIBMYSQL_PLUGIN_DIR environment variable can be set to the proper directory to enable plugin preloading to succeed.
• For explicit client plugin loading, themysql_load_plugin() andmysql_load_plugin_v() C API functions use theLIBMYSQL_PLUGIN_DIR value if it exists and the --plugin-dir option was not given. If--plugin-dir is given,mysql_load_plugin() andmysql_load_plugin_v() ignore LIBMYSQL_PLUGIN_DIR.

Return Values

A pointer to the plugin if it was loaded successfully.NULL if an error occurred.

Example

MYSQL mysql;

if(!mysql_load_plugin(&mysql, "myplugin",
                      MYSQL_CLIENT_AUTHENTICATION_PLUGIN, 0))
{
    fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
    exit(-1);
}