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// Copyright 2018 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. /// This macro creates a zero-overhead &CStr by adding a NUL terminator to /// the string literal passed into it at compile-time. Use it like: /// /// ``` /// let some_const_cstr = const_cstr!("abc"); /// ``` /// /// The above is roughly equivalent to: /// /// ``` /// let some_const_cstr = CStr::from_bytes_with_nul(b"abc\0").unwrap() /// ``` /// /// Note that macro only checks the string literal for internal NULs if /// debug-assertions are enabled in order to avoid runtime overhead in release /// builds. #[macro_export] macro_rules! const_cstr { ($s:expr) => ({ use std::ffi::CStr; let str_plus_nul = concat!($s, "\0"); if cfg!(debug_assertions) { CStr::from_bytes_with_nul(str_plus_nul.as_bytes()).unwrap() } else { unsafe { CStr::from_bytes_with_nul_unchecked(str_plus_nul.as_bytes()) } } }) }