我如何避免由拋出的異常 <thread> 在C ++ 11中？

Question

我正在嘗試使用C ++ 11中的線程庫編寫多線程軟件。 互聯網上的一些基本教程可以按預期進行編譯和運行。 但是我自己的應用程序分成多個類總是會引發異常。

誰能告訴我應該修復代碼的哪一部分？

$ clang++ -std=c++11 -stdlib=libc++ BaseInterface.cxx -c -o BaseInterface.o
$ clang++ -std=c++11 -stdlib=libc++ SocketReceiver.cxx -c -o SocketReceiver.o
$ clang++ -std=c++11 -stdlib=libc++ main.cxx -c -o main.o
$ clang++ -std=c++11 -stdlib=libc++ main.o BaseInterface.o SocketReceiver.o -o main
$ gdb main  
(gdb) run
Starting program: /Users/oxon/test/main 
Reading symbols for shared libraries ++............................ done
libc++abi.dylib: terminate called throwing an exception

Program received signal SIGABRT, Aborted.
[Switching to process 859 thread 0x40b]
0x00007fff88df8212 in __pthread_kill ()
(gdb) bt
#0  0x00007fff88df8212 in __pthread_kill ()
#1  0x00007fff8bc85af4 in pthread_kill ()
#2  0x00007fff8bcc9dce in abort ()
#3  0x00007fff894d3a17 in abort_message ()
#4  0x00007fff894d13c6 in default_terminate ()
#5  0x00007fff89874887 in _objc_terminate ()
#6  0x00007fff894d13f5 in safe_handler_caller ()
#7  0x00007fff894d1450 in std::terminate ()
#8  0x00007fff894d25b7 in __cxa_throw ()
#9  0x00007fff8a9ba3b9 in std::__1::thread::join ()
#10 0x0000000100000cf0 in SocketReceiver::Receive ()
#11 0x0000000100000c6d in SocketReceiver::DoReceive ()
#12 0x0000000100001593 in _ZNSt3__114__thread_proxyINS_5tupleIJPFPvS2_ES2_EEEEES2_S2_ ()
#13 0x00007fff8bc84742 in _pthread_start ()
#14 0x00007fff8bc71181 in thread_start ()

這是OS X 10.8上的結果。 帶有GCC 4.4的Scientific Linux 6也提供了類似的結果。

= BaseInterface.h =

#ifndef BASE_INTERFACE_H
#define BASE_INTERFACE_H

#include "SocketReceiver.h"

class BaseInterface
{
private:
  SocketReceiver*    fReceiver;

public:
  BaseInterface();
  virtual ~BaseInterface();

  virtual void Close();
  virtual void Open();
;

#endif

= BaseInterface.cxx =

#include <iostream>

#include <string.h>
#include <unistd.h>

#include "BaseInterface.h"

BaseInterface::BaseInterface()
{
  fReceiver = new SocketReceiver(this);
}

//______________________________________________________________________________
BaseInterface::~BaseInterface()
{
  Close();
  delete fReceiver;
  fReceiver = 0;
}

//______________________________________________________________________________
void BaseInterface::Close()
{
  fReceiver->Stop();
  usleep(10000);

  while(fReceiver->IsRunning()){
    usleep(10000);
  } // while
}

//______________________________________________________________________________
void BaseInterface::Open()
{
  fReceiver->Start();

}

= SocketReceiver.h =

#ifndef SOCKET_RECEIVER_H
#define SOCKET_RECEIVER_H

#include <thread>
#include <mutex>

class BaseInterface;

class SocketReceiver
{
private:
  BaseInterface*             fInterface;
  bool                       fIsRunning;
  std::mutex                 fMutex;
  bool                       fStop;
  std::thread*               fThread;

public:
  SocketReceiver(BaseInterface* interface = 0);
  virtual ~SocketReceiver();

  bool             IsRunning() const {return fThread ? true : false;}
  static void*     DoReceive(void* arg);
  void             Receive();
  void             Start();
  void             Stop();
};

#endif

= SocketReceiver.cxx =

#include <iostream>
#include <thread>
#include <unistd.h>

#include "BaseInterface.h"
#include "SocketReceiver.h"

SocketReceiver::SocketReceiver(BaseInterface* interface)
{
  fInterface = interface;
  fStop = true;
  fThread = 0;
}

//______________________________________________________________________________
SocketReceiver::~SocketReceiver()
{
}

//______________________________________________________________________________
void* SocketReceiver::DoReceive(void* arg)
{
  SocketReceiver* receiver = (SocketReceiver*)arg;
  receiver->Receive();

  return 0;
}

//______________________________________________________________________________
void SocketReceiver::Receive()
{
  while(not fStop){
    fMutex.lock();
    usleep(10000);
    fMutex.unlock();
  } // while

  fThread->join();

  delete fThread;
  fThread = 0;
}

//______________________________________________________________________________
void SocketReceiver::Start()
{
  fStop = false;
  fThread  = new std::thread(DoReceive, (void*)this);
}

//______________________________________________________________________________
void SocketReceiver::Stop()
{
  fStop = true;
}

= main.cxx =

#include "BaseInterface.h"

int main()
{
  BaseInterface interface;
  interface.Open();
  interface.Close();

  return 0;
}

Answer 1

您正在自己加入線程。 像在SocketReceiver::Stop一樣，在父線程中調用join 。

調用join ，它將清除基礎數據。 而且，如果您在正在運行的線程中調用它，那么該數據將在線程仍需要時被刪除。

Answer 2

如果由std::thread運行的函數通過和異常退出，則將調用std::terminate 。

std::thread::join()被指定拋出std::system_error錯誤代碼resource_deadlock_would_occur如果join()被調用在同一個線程，即線程不能加入本身。 因此，您嘗試使線程聯接本身會導致異常，從而終止進程。 線程無法連接自身，連接被定義為“等待線程完成”，因此顯然不能由線程本身完成，它將阻塞等待其自身完成，直到join()調用完成后才可能發生，這要等到線程完成后才能發生，而要等到join()調用完成后才可能發生...您能知道這是怎么回事嗎？

還有為什么要這么做？

fThread  = new std::thread(DoReceive, (void*)this);

std::thread不是pthread_create ，您不需要將其傳遞給void* ，只需擺脫DoReceive並調用：

fThread  = new std::thread(&SocketReceiver::Receive, this);

為什么您的std::thread分配了new ？ 也沒有必要，您可以使用std::thread成員並使用joinable()來檢查其是否處於活動狀態，而不是檢查指針是否為非null。