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// Copyright 2013-2016 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. /// Creates a `Vec` containing the arguments. /// /// `vec!` allows `Vec`s to be defined with the same syntax as array expressions. /// There are two forms of this macro: /// /// - Create a `Vec` containing a given list of elements: /// /// ``` /// let v = vec![1, 2, 3]; /// assert_eq!(v[0], 1); /// assert_eq!(v[1], 2); /// assert_eq!(v[2], 3); /// ``` /// /// - Create a `Vec` from a given element and size: /// /// ``` /// let v = vec![1; 3]; /// assert_eq!(v, [1, 1, 1]); /// ``` /// /// Note that unlike array expressions this syntax supports all elements /// which implement `Clone` and the number of elements doesn't have to be /// a constant. /// /// This will use `clone()` to duplicate an expression, so one should be careful /// using this with types having a nonstandard `Clone` implementation. For /// example, `vec![Rc::new(1); 5]` will create a vector of five references /// to the same boxed integer value, not five references pointing to independently /// boxed integers. #[cfg(not(test))] #[macro_export] #[stable(feature = "rust1", since = "1.0.0")] #[allow_internal_unstable] macro_rules! vec { ($elem:expr; $n:expr) => ( $crate::vec::from_elem($elem, $n) ); ($($x:expr),*) => ( <[_]>::into_vec(box [$($x),*]) ); ($($x:expr,)*) => (vec![$($x),*]) } // HACK(japaric): with cfg(test) the inherent `[T]::into_vec` method, which is // required for this macro definition, is not available. Instead use the // `slice::into_vec` function which is only available with cfg(test) // NB see the slice::hack module in slice.rs for more information #[cfg(test)] macro_rules! vec { ($elem:expr; $n:expr) => ( $crate::vec::from_elem($elem, $n) ); ($($x:expr),*) => ( $crate::slice::into_vec(box [$($x),*]) ); ($($x:expr,)*) => (vec![$($x),*]) } /// Use the syntax described in `std::fmt` to create a value of type `String`. /// See [`std::fmt`][fmt] for more information. /// /// [fmt]: ../std/fmt/index.html /// /// # Panics /// /// `format!` panics if a formatting trait implementation returns an error. /// This indicates an incorrect implementation /// since `fmt::Write for String` never returns an error itself. /// /// # Examples /// /// ``` /// format!("test"); /// format!("hello {}", "world!"); /// format!("x = {}, y = {y}", 10, y = 30); /// ``` #[macro_export] #[stable(feature = "rust1", since = "1.0.0")] macro_rules! format { ($($arg:tt)*) => ($crate::fmt::format(format_args!($($arg)*))) } // Private macro to get the offset of a struct field in bytes from the address of the struct. macro_rules! offset_of { ($container:path, $field:ident) => {{ // Make sure the field actually exists. This line ensures that a compile-time error is // generated if $field is accessed through a Deref impl. let $container { $field : _, .. }; // Create an (invalid) instance of the container and calculate the offset to its // field. Using a null pointer might be UB if `&(*(0 as *const T)).field` is interpreted to // be nullptr deref. let invalid: $container = ::core::mem::uninitialized(); let offset = &invalid.$field as *const _ as usize - &invalid as *const _ as usize; // Do not run destructors on the made up invalid instance. ::core::mem::forget(invalid); offset as isize }}; }