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《C++ 服务器开发精髓》随书配套源码

《C++ 服务器开发精髓》随书配套源码

这是《C++ 服务器开发精髓》的随书配套源码。

购买链接

https://item.jd.com/13312460.html

相关链接：

在 2021 年写一本 C++ 图书是一种什么体验？

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你可以加入本书读者交流群一起交流学习，加微信 easy_coder 拉你进群。

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mybooksources's Issues

linux信号量案例中47行任务队列tasks判空是否需要添加锁保护？

链接处代码第47行，调用tasks.empty() 前没有添加锁，而是在判空之后才加锁，这处代码在较高并发下情况下是否存在错误？我尝试将代码修改为每50毫秒产生一个任务，共计500个消费者线程进行消费，似乎没有发生任何错误。

		if (tasks.empty())
			continue;
		
		pthread_mutex_lock(&mymutex);	
		pTask = tasks.front();
		tasks.pop_front();
		pthread_mutex_unlock(&mymutex);
		
		pTask->doTask();
		delete pTask;

3.12.1 TaskPool.cpp 文件错误

运行代码片段3-5-4，并非如书本所说很难获得写锁，我的实验结果为： 在 centos 上几乎无法获得读锁，在 mac 上大约每获得5个读锁之后就能获得一个写锁

期待行为

运行程序，日志中显示极少次数获得了写锁

实际行为

在 centos 上几乎无法获得读锁，在 mac 上大约每获得5个读锁之后就能获得一个写锁

复现路径

mac

• mac 环境：

apples-Mac-mini-1243:~ apple$ g++ --version
Apple clang version 14.0.0 (clang-1400.0.29.202)
Target: x86_64-apple-darwin22.1.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
apples-Mac-mini-1243:~ apple$

• mac 上复现步骤：
  直接用Clion编译运行： https://github.com/LShuXin/cpp-server-development/tree/main/ch03/3.5/linux_rwlock01
  将输出以下结果：

/Users/apple/Desktop/linux_rwlock01/cmake-build-debug/linux_rwlock01
read threadID: read threadID: read threadID: 0x700002340000read threadID: 0x7000023c30000x70000223a0000x7000021b7000, resourceID: 0
, resourceID: 0, resourceID: 
read threadID: 0
0x7000022bd000, resourceID: 0, resourceID: 0

write threadID: 0x700002446000, resourceID:1
read threadID: 0x70000223a000, resourceID: 1
read threadID: read threadID: read threadID: 0x7000022bd000, resourceID: 1
0x7000023c3000read threadID: , resourceID: 0x700002340000, resourceID: 11

0x7000021b7000, resourceID: 1
write threadID: 0x700002446000, resourceID:2
read threadID: read threadID: 0x7000022bd0000x70000223a000, resourceID: , resourceID: 2
read threadID: read threadID: 20x7000021b7000
0x7000023c3000, resourceID: , resourceID: read threadID: 2
2
0x700002340000, resourceID: 2
write threadID: 0x700002446000, resourceID:3
read threadID: 0x7000021b7000, resourceID: 3
read threadID: 0x7000022bd000, resourceID: 3
read threadID: read threadID: 0x7000023c3000, resourceID: 30x700002340000
, resourceID: 3
read threadID: 0x70000223a000, resourceID: 3
write threadID: 0x700002446000, resourceID:4
read threadID: 0x7000021b7000, resourceID: 4
read threadID: read threadID: 0x7000023c3000, resourceID: 0x700002340000, resourceID: 4
read threadID: 0x7000022bd000, resourceID: 4
4

Linux

• Centos 环境：

[root@localhost cpp-server-development]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)
[root@localhost cpp-server-development]# g++ --version
g++ (GCC) 11.2.1 20220127 (Red Hat 11.2.1-9)
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

• Centos 复现步骤：

[root@localhost linux_rwlock01]# ls
CMakeLists.txt  main.cpp  README.md  test
[root@localhost linux_rwlock01]# pwd
/home/cpp-server-development/ch03/3.5/linux_rwlock01
[root@localhost linux_rwlock01]# g++ -std=c++11 -g -o test main.cpp -lpthread
[root@localhost linux_rwlock01]# ./test
read threadID: 140312867624704, resourceID: 0
read threadID: 140312901195520, resourceID: 0
read threadID: 140312892802816, resourceID: 0
read threadID: 140312884410112, resourceID: 0
read threadID: 140312876017408, resourceID: 0
read threadID: 140312867624704, resourceID: 0
read threadID: 140312901195520, resourceID: 0
read threadID: 140312892802816, resourceID: 0
read threadID: 140312884410112, resourceID: 0
read threadID: 140312876017408, resourceID: 0
read threadID: 140312867624704, resourceID: 0
read threadID: 140312901195520, resourceID: 0
read threadID: 140312892802816, resourceID: 0
read threadID: 140312884410112, resourceID: 0
read threadID: 140312876017408, resourceID: 0
read threadID: 140312867624704, resourceID: 0
read threadID: 140312901195520, resourceID: 0
read threadID: 140312892802816, resourceID: 0
read threadID: 140312884410112, resourceID: 0
read threadID: 140312876017408, resourceID: 0