Re: [Boost-users] How to pass data to thread

From: David Klein (dave_chp_at_[hidden])
Date: 2006-10-02 06:31:17

Monica Gretzer wrote:
> Hi,
>  
> I want to pass data to a thread function. My question is- what is 
> wrong with this code? The compiler error output is: "error: function 
> returning a function". In the code below I am trying to pass an int to 
> the thread function.
>  
> // ------------- code: how to pass data to the thread ? ----------------
> #include <boost/thread/thread.hpp>
> #include <boost/bind.hpp>
> #include <iostream>
>
> using namespace std;
>
> class TestThread
> {
> public:
>   void thread(int a);
>   void CreateThreads(void);
> };
>
> void TestThread::thread(int a)
> {
>   cout << "I am thread " << a << endl;
> }
>
> void TestThread::CreateThreads()
> {
>   boost::thread t1( boost::bind( &TestThread::thread, 10));
>   boost::thread t2( boost::bind( &TestThread::thread, 20));
>
>   // wait for the thread to finish
>   t1.join();
>   t2.join();
> }
>
> int main()
> {
>   TestThread t;
>   t.CreateThreads();
> }
hi monica,

either make TestThread::thread static ...

class TestThread
{
...
  static void thread(int a);
...
};

or use an instance of TestThread to bind to...

void TestThread::CreateThreads()
{
    TestThread tt;
  boost::thread t1( boost::bind( &TestThread::thread, tt, 10));
...
}

--
HTH dave