typedef struct sqlite3_context sqlite3_context;
The context in which an SQL function executes is stored in an sqlite3_context object. A pointer to an sqlite3_context object is always first parameter to application-defined SQL functions. The application-defined SQL function implementation will pass this pointer through into calls to sqlite3_result(), sqlite3_aggregate_context(), sqlite3_user_data(), sqlite3_context_db_handle(), sqlite3_get_auxdata(), and/or sqlite3_set_auxdata().
See also lists of Objects, Constants, and Functions.
SQLite is in the Public Domain.
https://sqlite.org/c3ref/context.html