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通过例子学习Rust

27 叛逆panic!

宏panic!用于在当前线程制造一个运行时错误（俗称叛逆）并开始栈回溯(stack unwinding)。 在回溯过程中，运行时(runtime)将负责调用析构函数，释放当前栈所拥有的(owned)所有对象的所有资源。

因为我们这个程序只有一个线程，panic!将导致该程序输出叛逆信息后结束运行。

// Re-implementation of integer division (/) fn division(dividend: int, divisor: int) -> int { if divisor == 0 { // Division by zero triggers a task panic panic!("division by zero"); } else { dividend / divisor } } // The `main` task fn main() { // Heap allocated integer let _x = box 0i; // This operation will trigger a task failure division(3, 0); println!("This point won't be reached!"); // `_x` should get destroyed at this point }

请看，panic!不会导致内存泄露。

$ rustc panic.rs && valgrind ./panic
==4401== Memcheck, a memory error detector
==4401== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==4401== Using Valgrind-3.10.0.SVN and LibVEX; rerun with -h for copyright info
==4401== Command: ./panic
==4401== 
task '<main>' panicked at 'division by zero', panic.rs:5
==4401== 
==4401== HEAP SUMMARY:
==4401==     in use at exit: 0 bytes in 0 blocks
==4401==   total heap usage: 18 allocs, 18 frees, 1,648 bytes allocated
==4401== 
==4401== All heap blocks were freed -- no leaks are possible
==4401== 
==4401== For counts of detected and suppressed errors, rerun with: -v
==4401== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)