C++11多线程与信号量

目录

最终目标：

纯线程无信号量

打印结果：

加入信号量同步

输出：

CMakeLists.txt

编译运行

最终目标：

1. c++类，创建3个线程，基类每隔1秒钟生产一个信号量，2个子类，消费信号量，达到同步效果

2. 以成员函数为线程

3. 基类创建线程，子类继承创建方法，重写线程函数

4. 3个线程修改全局变量g_nCount

纯线程无信号量

#include 
#include 
#include 

int g_nCount = 0;
class CBaseWorker
{
public:
    CBaseWorker(){}
    virtual ~CBaseWorker(){}

    void startJob()
    {
        m_bRunning = true;
        std::thread t(&CBaseWorker::ThreadFunc, this);
        //t.join();
        t.detach();
    }
private:
    virtual void ThreadFunc()
    {
        while(m_bRunning)
        {
           std::cout< 
打印结果： 
deMacBook-Pro demo % ./demo 

line:25  CBaseWorker...m_nCount=1
line:53 B Worker...m_nCount=2
line:40  A Worker...m_nCount=3

line:line:40  A Worker...m_nCount=4
25  CBaseWorker...m_nCount=5
line:53 B Worker...m_nCount=6
line:
line:25  CBaseWorker...m_nCount=7
40  A Worker...m_nCount=line:538
 B Worker...m_nCount=9

line:53 B Worker...m_nCount=10
line:40  A Worker...m_nCount=line:11
25  CBaseWorker...m_nCount=12
line:53 B Worker...m_nCount=13
line:40  A Worker...m_nCount=14

line:25  CBaseWorker...m_nCount=15
line:
line:25  CBaseWorker...m_nCount=16
53 B Worker...m_nCount=17
line:40  A Worker...m_nCount=18

line:25  CBaseWorker...m_nCount=19
line:53 B Worker...m_nCount=20
line:40  A Worker...m_nCount=21

line:25  CBaseWorker...m_nCount=22
line:40  A Worker...m_nCount=23
line:53 B Worker...m_nCount=24

line:line:25  CBaseWorker...m_nCount=25
line:53 B Worker...m_nCount=4026
  A Worker...m_nCount=27

**************  exit()  *****************
deMacBook-Pro demo % 
 
可以看出来，打印相当的混乱。
 
 
加入信号量同步 
#include 
#include 
#include 
#include 
#include 

int g_nCount = 0;
sem_t *g_pSem = nullptr; //信号量
class CBaseWorker
{
public:
    CBaseWorker(){
    }
    virtual ~CBaseWorker(){
    }

    //启动线程
    void startJob()
    {
        m_bRunning = true;
        std::thread t(&CBaseWorker::ThreadFunc, this);
        //t.join();
        t.detach();
    }

    //停止线程
    void stopJob()
    {
        m_bRunning = false;

        // printSem(__LINE__);
        // //macos下，一个生产者+多个消费者，结束任务时，需要sem_post，否则会出现sem_close阻塞的情况，原因不明；linux正常；
        // while(sem_trywait(g_pSem))
        // {
        //     printSem(__LINE__);
        //     std::cout<<"line:"<<__LINE__<<"  will stop sem..."<>>> sem_getvalue error... ret="<>>> sem_getvalue nSemValue="< 
输出： 
[root@VM-20-16-centos demo]# ./demo 
sem_open success.

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:77 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=1
line:77 >>>> sem_getvalue nSemValue=0
line:96 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=2
line:77 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:99 >>>> sem_getvalue nSemValue=0
line:100 B Worker...m_nCount=3
line:96 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=4
line:77 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:99 >>>> sem_getvalue nSemValue=0
line:100 B Worker...m_nCount=5
line:96 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=6
line:77 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:99 >>>> sem_getvalue nSemValue=0
line:100 B Worker...m_nCount=7
line:96 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=8
line:77 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:99 >>>> sem_getvalue nSemValue=0
line:100 B Worker...m_nCount=9
line:96 >>>> sem_getvalue nSemValue=0

line:59  send sem...
line:62 >>>> sem_getvalue nSemValue=1
line:80 >>>> sem_getvalue nSemValue=0
line:81  A Worker...m_nCount=10
line:77 >>>> sem_getvalue nSemValue=0

**************  exit()  *****************
line:139 >>>> sem_getvalue nSemValue=0
************** sem_close  *****************
**************  sem_unlink  *****************
[root@VM-20-16-centos demo]# 
 
CMakeLists.txt 
注意大小写敏感
 
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
PROJECT(demo)

add_compile_options(-std=c++11)

INCLUDE_DIRECTORIES(
    ${CMAKE_CURRENT_LIST_DIR}/
)

FILE(GLOB COMMON
    ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp
)

FILE(GLOB SOURCES
    ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp
)

ADD_EXECUTABLE(
    ${PROJECT_NAME} 
    ${SOURCES}
    ${COMMON}
)

TARGET_LINK_LIBRARIES(
    ${PROJECT_NAME}
    pthread
)
 
编译运行 
cmake .
 
make
 
./demo