Question

Possible Duplicate:
pthread Function from a Class

I am fairly new to c++ and I am doing a project regarding TCP.

I need to create a thread so I googled and found this.
http://www.yolinux.com/TUTORIALS/LinuxTutorialPosixThreads.html

I follow its syntax but encounter errors:
argument of type ‘void* (ns3::TcpSocketBase::)()’ does not match ‘void* ()(void)’

codes:

tcp-socket-base.h:
class TcpSocketBase : public TcpSocket
{
 public:
 ...
 void *threadfunction();
 ....
}




tcp-socket-base.cc:

void
*TcpSocketBase::threadfunction()
{
//do something
}



..//the thread was create and the function is called here
pthread_t t1;
int temp  =  pthread_create(&t1, NULL, ReceivedSpecialAck, NULL); //The error happens here
return;
...

Any help would be appreciated. Thanks!

EDIT:

I took the advise and make the threadfunction a non member function.

namespaceXXX{

void *threadfunction()


int result  =  pthread_create(&t1, NULL, threadfunction, NULL);
      NS_LOG_LOGIC ("TcpSocketBase " << this << " Create Thread returned result: " << result );

void *threadfunction()
{
 .....
}


}

But I got this error instead:

initializing argument 3 of ‘int pthread_create(pthread_t*, const pthread_attr_t*, void* ()(void), void*)’ [-fpermissive]

Answer 1

If you’d like to continue using pthreads, a simple example is:

#include <cstdio>
#include <string>
#include <iostream>

#include <pthread.h>

void* print(void* data)
{
    std::cout << *((std::string*)data) << "\n";
    return NULL; // We could return data here if we wanted to
}

int main()
{
    std::string message = "Hello, pthreads!";
    pthread_t threadHandle;
    pthread_create(&threadHandle, NULL, &print, &message);
    // Wait for the thread to finish, then exit
    pthread_join(threadHandle, NULL);
    return 0;
}

A better alternative, if you’re able to, is to use the new C++11 thread library. It’s a simpler, RAII interface that uses templates so that you can pass any function to a thread, including class member functions (see this thread).

Then, the above exmaple simplifies to this:

#include <cstdio>
#include <string>
#include <iostream>

#include <thread>

void print(std::string message)
{
    std::cout << message << "\n";
}

int main()
{
    std::string message = "Hello, C++11 threads!";
    std::thread t(&print, message);
    t.join();
    return 0;
}

Note how you can just pass data directly in – casts to and from void* are not needed.