= note: values in a scope are dropped in the opposite order they are defined error[E0515]: cannot return value referencing local variable `cmd` --> src/main.rs:31:1 | 24 | codeV = re.captures(cmd.as_str()); | --- `cmd` is borrowed here ... 31 | V //Error | ^ returns ...
红区(redzone)是System V ABI提供的一种优化的产物,它允许函数无需调整栈指针(stack pointer),便能临时使用其栈帧(stack frame)下方的128个字节: 这张图片展示了一个有n个局部变量(local variable)的函数的栈帧。在进入函数时,两个指令(instruction)将栈指针调节到合适的位置,以便为返回地址(return address)和局...
和策略1的情况类似,但这次我们没有得到error[E0597]: 'x' does not live long enough,而是得到error[E0515]: cannot return reference to local variable 'x'。 在函数里创建的数据,不能将其引用作为返回值。因为函数调用结束后,所有权属于函数的数据,将会自动释放,这样会违反策略1。 据此,我们得到一条推论:...
fntest(r:&i32)->&i32{letx=5;println!("r is: {}",r);&x} 和策略1的情况类似,但这次我们没有得到error[E0597]: 'x' does not live long enough,而是得到error[E0515]: cannot return reference to local variable 'x'。 在函数里创建的数据,不能将其引用作为返回值。因为函数调用结束后,所有权...
error[E0515]: cannot return value referencing local variable `delim` --> src/lib.rs:41:5|41 | StrSplit::new(s, &delim)| ^ --- `delim` is borrowed here| ___|| |42 | | .next()43 | | .expect("StrSplit should have at least one result")| |___^ returns a value referencing...
return Err(MethodCallFailed::ExceptionThrown(exception)); } Ok(Some(catch_handler_pc)) => { // Re-push exception on the stack and continue // execution of this method from the catch handler self.stack.push(Value::Object(exception.0))?; ...
{returnty;}unreachable!()}else{self.next_ty_var(TypeVariableOrigin{kind:TypeVariableOriginKind::TypeInference,span,})}}// Impl inferCtxtpub fnnext_ty_var(&self,origin:TypeVariableOrigin)->Ty<'tcx>{self.tcx.mk_ty_var(self.next_ty_var_id(origin))}#[inline]pub fnmk_ty_var(self,v:...
{returntrue;}if search_key < vec[_mid] {high = _mid - 1;}elseif search_key > vec[_mid] {low = _mid + 1;}}returnfalse;}fn main() {let mut _rng = thread_rng();let mut int_vec = Vec::new();let max_num = 1000000;fornumin1..max_num {int_vec.push(numasi32);}let ...
fn get_hash_map() -> Option<Vec<i32>> { let mut hm = HashMap::new(); let mut vec = Vec::new(); vec.push(1); hm.insert("1".to_string(), vec); return hm.remove("1"); } remove将值移出映射,返回为Option<V>。如果你需要一个Option<&Vec<i32>>,你可以在你的Option<Vec<i32...
None=>return, }; letmutsprite_clone = sprite.clone; sprite.schedule(once(move|mutco|asyncmove{ foriin(1..=3).rev { p!("{}", i); sleep!(co,1.0); } p!("Hello World"); sprite_clone.perform_def(ActionDef::sequence(&vec![ ...