我在下面的第一代码段(在GenericMessage.hxx定义)所示的名为GenericMessage类。ZMQ:发送自定义对象CPP在ZMQ队列
我有一个名为TestFE.cpp的文件(见下面的第二个代码片段),它试图通过ZMQ队列发送类GenericMessage的一个实例(另请参阅第四个代码片段 - ZmqHandler.hxx)。 TesfFE.cpp通过包含ZmqHandler.hxx来实现ZMQ推送模式。
我还没有命名TestBE.cpp另一个.cpp文件(见下面的第三个代码段),其接收这样通过ZMQ队列中提到GenericMessage实例。 TestBE.cpp在这里实现ZMQ拉取模式以通过ZMQ队列检索GenericMessage实例。
在TestFE.cpp,我使用标准memcpy函数,以便将GenericMessage对象转换成可由ZMQ队列被接受的形式。在TestBE.cpp的第21行(在注释中的第三个代码片段中标记),我得到了一个分段错误,因为它看起来memcpy在发送端TestFE.cpp上无法正常工作。 TestBE执行时,我收到了下面的消息。我也在下面提供gdb回溯。你能告诉我这里有什么问题吗?为什么你认为memcpy无法正确地将我的GenericMessage对象复制到ZMQ message_t格式?或者你认为这个问题还是别的?任何意见将不胜感激。
ERROR MESSAGE
$ ./TestBE
Connecting to FE...
RECEIVED: 1
Segmentation fault (core dumped)
GDB回溯
(gdb) r
Starting program: /home/holb/HOLB_DESIGN/ZMQ/WORK1/TestBE
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[New Thread 0xb7c84b40 (LWP 4252)]
[New Thread 0xb7483b40 (LWP 4253)]
Connecting to FE...
RECEIVED: 1
Program received signal SIGSEGV, Segmentation fault.
0xb7f371cc in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::string const&)()
from /usr/lib/i386-linux-gnu/libstdc++.so.6
(gdb) bt
#0 0xb7f371cc in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::string const&)()
from /usr/lib/i386-linux-gnu/libstdc++.so.6
#1 0x08049621 in GenericMessage<std::string>::getData (this=0xbffff06c)
at GenericMessage.hxx:18
#2 0x08049075 in main() at TestBE.cxx:21
(gdb)
代码段1(GenericMessage.hxx) 的#include 的#include 的#include
template <class T>
class GenericMessage {
public:
GenericMessage(int id, T msg):
beId(id),
data(msg)
{}
~GenericMessage(){}
T getData()
{
//LINE 18 is the following line!
return data;
}
std::string toString()
{
std::ostringstream ss;
ss << getBeId();
std::string ret = ss.str();
return ret;
}
void setBeId(int id)
{
beId = id;
}
int getBeId()
{
return beId;
}
private:
int beId;
T data;
};
代码段2(TestFE.cxx ==>发送者) 的#include “ZmqHandler.hxx” // SEE的第四代码段在底部ZmqHandler.hxx
int main()
{
ZmqHandler<std::string> zmqHandler;
int counter = 1;
while(1)
{
std::string data = "Hello there!\0";
GenericMessage<std::string> msg(counter, data);
zmqHandler.sendToBE(&msg);
counter++;
sleep(1);
}
return 0;
}
的内容
代码段3(TestBE.cxx ==>接收机)
#include "zmq.hpp"
#include "GenericMessage.hxx"
#include <string>
#include <iostream>
int main()
{
// Prepare our context and socket
zmq::context_t context (1);
zmq::socket_t socket (context, ZMQ_PULL);
std::cout << "Connecting to FE..." << std::endl;
socket.connect ("tcp://localhost:5555");
while(1){
zmq::message_t reply;
socket.recv (&reply);
GenericMessage<std::string> *msg = (GenericMessage<std::string>*)(reply.data());
std::cout << "RECEIVED: " << msg->toString() << std::endl;
/* ********************************* */
/* SEGMENTATION FAULT HAPPENS HERE */
/* The member "data" in class GenericMessage cannot be received while the member "id" in the previous line can be received. */
std::cout << "DATA: " << ((std::string)msg->getData()) << std::endl;
/* ********************************** */
}
return 0;
}
代码段4(ZMQHandler.hxx)
#include "zmq.hpp"
#include "GenericMessage.hxx"
#include <pthread.h>
#include <unistd.h>
#include <cassert>
template <class T>
class ZmqHandler {
public:
ZmqHandler():
mContext(1),
mOutbHandlerSocket(mContext, ZMQ_PUSH)
{
mOutbHandlerSocket.bind ("tcp://*:5555");
}
~ZmqHandler() {}
void *sendToBE(GenericMessage<T> *theMsg)
{
// Place the new request to the zmq queue for BE consumption
zmq::message_t msgToSend(sizeof(*theMsg));
memcpy (msgToSend.data(), ((GenericMessage<T>*)theMsg), sizeof(* ((GenericMessage<T>*)theMsg)));
mOutbHandlerSocket.send(msgToSend);
std::cout << "SENT request: [" << theMsg->toString() << "]" << std::endl;
return (NULL);
}
private:
zmq::context_t mContext;
zmq::socket_t mOutbHandlerSocket;
};
我为标题ZMQ没有遗憾......它可能不是ZMQ失败,而我的代码。所以,如果有人被冒犯,标题不是无意的,并且很抱歉。 –
如果你能指出文件GenericMessage.hxx中的第18行,这将有所帮助。此外,您可以使用GDB的'up'命令上传调用堆栈,因此当您到达代码时,您可以检查变量以查看它们的值。 –
谢谢,我只是在包含GenericMessage.hxx的第一个代码片段中指出第18行。 –