Hi Steven and other guys,
Thanks for Steven's input. Is the following code correct?
class FileThread
{
public:
void find() { std::cout << "FileThread::find() called" << std::endl;}
void print() { std::cout << "FileThread::print() called" << std::endl;}
};
class group_helper
{
private:
boost::shared_ptr<FileThread> m_object;
public:
group_helper() : m_object(boost::shared_ptr<FileThread>(new FileThread))
{ std::cout << "group_helper::ctor called" << std::endl;}
void operator()() { m_object->find(); m_object->print(); }
~group_helper() { std::cout << "group_helper::***dtor called" << std::endl; }
};
int main()
{
group_helper gp;
boost::thread_group threads;
for (int i = 0; i < 1; ++i)
threads.create_thread(gp);
threads.join_all();
return 0;
}
===========
Output: 1 call to "group_helper::ctor called"
6 calls to "group_helper::***dtor called"
===========
If the code is correct, does this mean that with thread_group we can no longer expect the # of ctors matches that of the dtors in threaded code?
Thanks in advance,
Robert
AMDGBoth are correct depending on whether you want to pass an external FileThread
Boost lzw wrote:
I have two versions (VERSION1 and VERSION2) of a group_helper functor to be
called from boost::thread_group, which one of them is correct?
class FileThread
{
public:
void print() {...}
void find() {...}
};
class group_helper
{
private:
boost::shared_ptr<FileThread> m_object;
public:
//VISION1
group_helper(boost::shared_ptr<FileThread>& object) : m_object(object) {
}
//VISION2
group_helper() : m_object(boost::shared_ptr<FileThread>(new FileThread))
{ }
void operator()() { m_object->find(); m_object->print(); }
};
or create a new FileThread in the constructor.group_helper is copied and both copies try to
On another matter, why the following code results in a runtime exception
from the group_helper's dtor?
#include <iostream>
#include "boost/thread/thread.hpp"
class FileThread
{
public:
void find() { }
void print() { }
};
class group_helper
{
private:
FileThread* m_object;
public:
group_helper() : m_object(new FileThread) {}
void operator()() { m_object->find(); m_object->print(); }
~group_helper() { if (m_object) delete m_object; }// EXCEPTION from dtor
};
delete m_object.In Christ,
int main()
{
group_helper gh;
boost::thread thrd(gh);
thrd.join();
}
Steven Watanabe
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