1 2scopeguard 3========== 4 5Rust crate for a convenient RAII scope guard that will run a given closure when 6it goes out of scope, even if the code between panics (assuming unwinding panic). 7 8The `defer!` macro and `guard` are `no_std` compatible (require only core), 9but the on unwinding / not on uwinding strategies requires linking to `std`. 10 11Requires Rust 1.20. 12 13 14Please read the `API documentation here`__ 15 16__ https://docs.rs/scopeguard/ 17 18|build_status|_ |crates|_ 19 20.. |build_status| image:: https://travis-ci.org/bluss/scopeguard.svg 21.. _build_status: https://travis-ci.org/bluss/scopeguard 22 23.. |crates| image:: http://meritbadge.herokuapp.com/scopeguard 24.. _crates: https://crates.io/crates/scopeguard 25 26How to use 27---------- 28 29.. code:: rust 30 31 #[macro_use(defer)] extern crate scopeguard; 32 33 use scopeguard::guard; 34 35 fn f() { 36 defer!(println!("Called at return or panic")); 37 panic!(); 38 } 39 40 use std::fs::File; 41 use std::io::Write; 42 43 fn g() { 44 let f = File::create("newfile.txt").unwrap(); 45 let mut file = guard(f, |f| { 46 // write file at return or panic 47 let _ = f.sync_all(); 48 }); 49 // Access the file through the scope guard itself 50 file.write_all(b"test me\n").unwrap(); 51 } 52 53Recent Changes 54-------------- 55 56- 1.1.0 57 58 - Change macros (``defer!``, ``defer_on_success!`` and ``defer_on_unwind!``) 59 to accept statements. (by @konsumlamm) 60 61- 1.0.0 62 63 - Change the closure type from ``FnMut(&mut T)`` to ``FnOnce(T)``: 64 Passing the inner value by value instead of a mutable reference is a 65 breaking change, but allows the guard closure to consume it. (by @tormol) 66 67 - Add ``defer_on_success!{}``, ``guard_on_success()`` and ``OnSuccess`` 68 strategy, which triggers when scope is exited *without* panic. It's the 69 opposite to ``OnUnwind`` / ``guard_on_unwind()`` / ``defer_on_unwind!{}``. 70 71 - Add ``ScopeGuard::into_inner()``, which "defuses" the guard and returns the 72 guarded value. (by @tormol) 73 74 - Implement ``Sync`` for guards with non-``Sync`` closures. 75 76 - Require Rust 1.20 77 78- 0.3.3 79 80 - Use ``#[inline]`` on a few more functions by @stjepang (#14) 81 - Add examples to crate documentation 82 83- 0.3.2 84 85 - Add crate categories 86 87- 0.3.1 88 89 - Add ``defer_on_unwind!``, ``Strategy`` trait 90 - Rename ``Guard`` → ``ScopeGuard`` 91 - Add ``ScopeGuard::with_strategy``. 92 - ``ScopeGuard`` now implements ``Debug``. 93 - Require Rust 1.11 94 95- 0.2.0 96 97 - Require Rust 1.6 98 - Use `no_std` unconditionally 99 - No other changes 100 101- 0.1.2 102 103 - Add macro ``defer!()`` 104
