From c395f4d32a7ce1e9505e817eab6226d48144db06 Mon Sep 17 00:00:00 2001 From: lisongqian Date: Mon, 21 Aug 2023 14:30:22 +0800 Subject: [PATCH] Fix RwLock in sync1.md Fixes: #1262 Signed-off-by: lisongqian --- src/advance/concurrency-with-threads/sync1.md | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/src/advance/concurrency-with-threads/sync1.md b/src/advance/concurrency-with-threads/sync1.md index a37ac58a..93f59abe 100644 --- a/src/advance/concurrency-with-threads/sync1.md +++ b/src/advance/concurrency-with-threads/sync1.md @@ -382,7 +382,7 @@ fn main() { *w += 1; assert_eq!(*w, 6); - // 以下代码会panic，因为读和写不允许同时存在 + // 以下代码会阻塞发生死锁，因为读和写不允许同时存在 // 写锁w直到该语句块结束才被释放，因此下面的读锁依然处于`w`的作用域中 // let r1 = lock.read(); // println!("{:?}",r1); @@ -390,14 +390,9 @@ fn main() { } ``` -`RwLock`在使用上和`Mutex`区别不大，需要注意的是，当读写同时发生时，程序会直接`panic`(本例是单线程，实际上多个线程中也是如此)，因为会发生死锁： +`RwLock`在使用上和`Mutex`区别不大，只有在多个读的情况下不阻塞程序，其他如读写、写读、读读情况下均会对后获取锁的操作进行阻塞。 -```console -thread 'main' panicked at 'rwlock read lock would result in deadlock', /rustc/efec545293b9263be9edfb283a7aa66350b3acbf/library/std/src/sys/unix/rwlock.rs:49:13 -note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace -``` - -好在我们可以使用`try_write`和`try_read`来尝试进行一次写/读，若失败则返回错误: +我们也可以使用`try_write`和`try_read`来尝试进行一次写/读，若失败则返回错误: ```console Err("WouldBlock")