Issue with thread_specific_ptr data deletion at thread end - multithreading

Question

I use the thread local storage with boost.
I have a global variable :
boost::thread_specific_ptr<MyDataClass> p_timeline_ctx;
and I have the following class, which encapsulates a boost::thread object and contains an additionnal data object :
class MyThread {
private :
boost::thread t;
MyDataClass d;
public :
MyThread():c() {}
void start(void) {
ptr.reset(this->d);
this->t = boost::thread(&MyThread::worker, this);
}
void worker(void) {
// do something
}
};
I do not get any error when compiling. But on runtime, when the worker function exits and the thread ends, I get a "glibc ... free ... invalid pointer" error.
I guess this comes from the fact that, according to the boost doc, the thread_specific_ptr tries to delete the object it points to when threads end. But I do not see how to solve the problem.

Answer 1

The thread specific pointer takes ownership. You could reset it:
p_timeline_ctx.reset(0);
or intialize it with a deep copy in the first place:
ptr.reset(new MyDataStruct(d));
However, you'd be far better off just passing the reference as an argument to the thread pointer.
In fact, the worker is already an instance member function, so, why do you need a thread-specific copy of this:
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <iostream>
struct MyDataClass { };
class MyThread {
private :
boost::thread t;
MyDataClass d;
public :
MyThread(): d() {}
void start(void) {
t = boost::thread(&MyThread::worker, this);
}
void worker() {
// just use this->d here
}
};
int main()
{
}
Or using a static thread function:
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <iostream>
struct MyDataClass { };
class MyThread {
private :
boost::thread t;
MyDataClass d;
public :
MyThread(): d() {}
void start(void) {
t = boost::thread(&MyThread::worker, boost::ref(d));
}
static void worker(MyDataClass&) {
// do something
}
};
int main()
{
}