[Boost-users] help: boost::thread and compile error

From: Guillermo Martony (gmartony_at_[hidden])
Date: 2004-05-10 09:12:05

Greetings,
The following code taken from an example compiles without errors:

#include <boost/thread/thread.hpp>
#include <boost/thread/xtime.hpp>
#include <iostream>
class thread_alarm
{
public:
    thread_alarm(int secs) : m_secs(secs) { }
    void operator()()
    {
        boost::xtime xt;
        boost::xtime_get(&xt, boost::TIME_UTC);
        xt.sec += m_secs;
        boost::thread::sleep(xt);
        std::cout << "alarm sounded..." << std::endl;
}
private:
    int m_secs;
};

int main()
{
    int secs = 5;
    std::cout << "setting alarm for 5 seconds..." << std::endl;
    thread_alarm alarm(secs);
    boost::thread thrd(alarm);
    thrd.join();
    return 0;
}

But adding a std::fstream varible to the thread_alarm class:

#include <fstream>
#include <boost/thread/thread.hpp>
#include <boost/thread/xtime.hpp>
#include <iostream>
class thread_alarm
{
public:
    thread_alarm(int secs) : m_secs(secs) { }
    void operator()()
{
    boost::xtime xt;
    boost::xtime_get(&xt, boost::TIME_UTC);
    xt.sec += m_secs;
    boost::thread::sleep(xt);
    std::cout << "alarm sounded..." << std::endl;
}
private:
    int m_secs;
    std::fstream fs;        // only this line was added
};

int main()
{
    int secs = 5;
    std::cout << "setting alarm for 5 seconds..." << std::endl;
    thread_alarm alarm(secs);
    boost::thread thrd(alarm);
    thrd.join();
    return 0;
}

Results in the following compilation error:

c:\opt\include\boost\function\function_template.hpp(289): error C2664: 'void
boost::function0<R,Allocator>::assign_to(Functor)' : cannot convert
parameter 1 from 'const thread_alarm' to 'thread_alarm'
        with
        [
            R=void,
            Allocator=int,
            Functor=thread_alarm
        ]

I'm using Microsoft Studio .NET  2002

Thanks in advance for any help.
Guillermo Martony