Function duckdb_client_context_get_catalog 

pub unsafe extern "C" fn duckdb_client_context_get_catalog(
    context: duckdb_client_context,
    catalog_name: *const c_char,
) -> duckdb_catalog

Retrieve a database catalog instance by name. This function can only be called from within the context of an active transaction, e.g. during execution of a registered function callback. Otherwise returns nullptr. @param context The client context. @param catalog_name The name of the catalog. @return The resulting catalog instance, or nullptr if called from outside an active transaction or if a catalog with the specified name does not exist. Must be destroyed with duckdb_destroy_catalog