#include #include #include //#include

#include #include

#include #include #include #include #include #include

namespace muduo{namespace CurrentThread{ // __thread修饰的变量是线程局部存储的。多个线程并不会去共享他，每个线程都有1份 __thread int t_cachedTid = 0; // 线程真实pid（tid）的缓存， // 是为了减少::syscall(SYS_gettid)系统调用的次数 // 提高获取tid的效率 __thread char t_tidString[32]; // 这是tid的字符串表示形式 __thread const char* t_threadName = "unknown";//线程的名称 const bool sameType = boost::is_same::value;//boost::is_same作用：若int和pid_t是相同类型的，则返回是true BOOST_STATIC_ASSERT(sameType);}

namespace detail{

pid_t gettid(){ return static_cast(::syscall(SYS_gettid));}

void afterFork(){ muduo::CurrentThread::t_cachedTid = 0;//子进程中当前线程的tid=0 muduo::CurrentThread::t_threadName = "main"; CurrentThread::tid();//缓存一下tid // no need to call pthread_atfork(NULL, NULL, &afterFork);}

/*（1）namespace detail中的pthread_atfork意义在于：fork可能是在主线程中调用，也可能是在子线程中调用，fork得到一个新进程，新进程中只有1个执行序列，只有1个线程(调用fork的线程被继承下来)

（2）实际上，对于编写多线程程序来说，我们最好不要调用fork，不要编写多线程多进程程序，要么是用多进程，要么用多线程*/

class ThreadNameInitializer{ public: ThreadNameInitializer() { muduo::CurrentThread::t_threadName = "main";//主线程的名称为main CurrentThread::tid();//缓存当前线程的tid到t_cachedTid中 pthread_atfork(NULL, NULL, &afterFork);//若调用成功，则子进程则会调用afterFork }};

ThreadNameInitializer init;//在detail名称空间中，先于main函数}}

using namespace muduo;

void CurrentThread::cacheTid(){ if (t_cachedTid == 0) { t_cachedTid = detail::gettid();//detail名称空间的gettid() int n = snprintf(t_tidString, sizeof t_tidString, "%5d ", t_cachedTid); assert(n == 6); (void) n;//(void) n作用：防止release版本编译不通过，因为release版本编译的时候，assert(n == 6)这条语句 //相当于没有，那么上一条语句的n相当于没用 }}

bool CurrentThread::isMainThread(){ return tid() == ::getpid();}

AtomicInt32 Thread::numCreated_;

Thread::Thread(const ThreadFunc& func, const string& n) : started_(false), pthreadId_(0), tid_(0), func_(func), name_(n){ numCreated_.increment();//原子操作，线程个数+1}

Thread::~Thread(){ // no join}

void Thread::start(){ assert(!started_); started_ = true; errno = pthread_create(&pthreadId_, NULL, &startThread, this); if (errno != 0) { //LOG_SYSFATAL runInThread(); return NULL;}

void Thread::runInThread(){ tid_ = CurrentThread::tid();//获取线程tid muduo::CurrentThread::t_threadName = name_.c_str(); try { func_();//调用回调函数 muduo::CurrentThread::t_threadName = "finished"; } catch (const Exception& ex) { muduo::CurrentThread::t_threadName = "crashed"; fprintf(stderr, "exception caught in Thread %s\n", name_.c_str()); fprintf(stderr, "reason: %s\n", ex.what()); fprintf(stderr, "stack trace: %s\n", ex.stackTrace()); abort(); } catch (const std::exception& ex) { muduo::CurrentThread::t_threadName = "crashed"; fprintf(stderr, "exception caught in Thread %s\n", name_.c_str()); fprintf(stderr, "reason: %s\n", ex.what()); abort(); } catch (...) { muduo::CurrentThread::t_threadName = "crashed"; fprintf(stderr, "unknown exception caught in Thread %s\n", name_.c_str()); throw; // rethrow }}