sqlite3_module —
Virtual Table Object
This structure, sometimes called a "virtual table module", defines the
  implementation of a virtual tables. This structure consists mostly of methods
  for the module.
A virtual table module is created by filling in a persistent
    instance of this structure and passing a pointer to that instance to
    sqlite3_create_module() or sqlite3_create_module_v2(). The registration
    remains valid until it is replaced by a different module or until the
    database connection closes. The content of this structure must not change
    while it is registered with any database connection.