Question

I am working on network programming using epoll and I have this code.

            int str_len = read(m_events[i].data.fd, buf, BUF_SIZE);
            printf("read %d \n", str_len);

            if(str_len == 0){
                if(!removeClient(m_events[i].data.fd))
                    break;
                close(m_events[i].data.fd);

            }
            else {
                printf("ServerManager::eventAcceptLoop, A message has been received \n");
                pushWork(buf);
            }

the buf is declared like this

buf[BUF_SIZE];

and I want to pass the data in the buf to the functiion “pushWork”

 pushWork(char * pdata){
      hand this pdata to the thread pool to parse and handle it
 }

I think I need to copy the data in the buf instead of pointing to the buf because it will be overriden whenever a new data comes in. Right now I do something like

 char *pdata = buf;
 pushWork(pdata)

Should I do memcopy or something else? and flush the buf?
Please let me know how I can handle this. Thanks in advance…

Answer 1

Yes, you can copy the data:

char* pdata = new char[str_len];
memcpy(pdata, buf, str_len);
pushWork(pdata);

At the pushWork end, it has to take care of freeing the data when it’s done:

delete[] pdata;

---

You will also want to consider encapsulating this all into a std::vector so you don’t have to worry about exception safety:

std::vector<char> data(buf, buf + str_len);
pushWork(data);

In this case, pushWork needs to be modified to take a std::vector by value, but the upside is that it won’t have to worry about deleting the data when done, and will be fully exception-safe.