Re: [Boost-users] boost::thread maybe have bug.

From: Doug Gregor (dgregor_at_[hidden])
Date: 2004-11-03 11:01:43

On Nov 3, 2004, at 10:28 AM, ~{5EH}BV5D~} wrote:

> Recently, I download boost 1.31.0 and compile it with Visual 
> studio.net 2003.
> But the code below can't work properly:
>
> class A
> {
> public:
>   A() { printf("constructor.\n"); }
>
>   ~~A() { printf("destructor.\n"); }
>
>   void operator () () { }
> };
>
> int main(int argc, char* argv[])
> {
>   A a;
>   boost::thread t(a);
>   t.join();
> }
>
> In my system, it generate the message like this:
> D:\thread\Debug>thread.exe
> constructor.
> destructor.
> destructor.
> destructor.
> destructor.
> destructor.
> destructor.
>
> Who can tell me what's wrong with boost or something else?

The A object is being copied several times. Add in a constructor like 
this to see what is going on:

   A(const A&) { printf("copy constructor.\n"); }

If you really don't want copying to occur, use:

   boost::thread t(boost::ref(a));

        Doug