Function libsqlite3_sys::sqlite3_create_function

pub unsafe extern fn sqlite3_create_function(db: *mut sqlite3,
                                             zFunctionName: *const c_char,
                                             nArg: c_int,
                                             eTextRep: c_int,
                                             pApp: *mut c_void,
                                             xFunc: Option<unsafe extern fn(_: *mut sqlite3_context, _: c_int, _: *mut *mut sqlite3_value)>,
                                             xStep: Option<unsafe extern fn(_: *mut sqlite3_context, _: c_int, _: *mut *mut sqlite3_value)>,
                                             xFinal: Option<unsafe extern fn(_: *mut sqlite3_context)>)
                                             -> c_int