sqlite3_sys::sqlite3_create_function

pub unsafe extern fn sqlite3_create_function(p: *mut sqlite3, p: *const c_char, n: c_int, n: c_int, p: *mut c_void, f: Option<sqlite3_create_function_callback1>, f: Option<sqlite3_create_function_callback1>, f: Option<sqlite3_create_function_callback2>) -> c_int