--- In Boost-Users@y..., Luis De la Parra <lparrab@g...> wrote:
On Monday 16 September 2002 16:50, Marcio Del'Valle wrote:
Hi there,
When I use boost::thread for creating multiple threads I notice that the destructor of object I pass as an argument ( boost::thread (*pObjetc) ) is called twice. Why does it happen?
because boost makes a copy (acutally several!!) of the object, and then destroys them. boost calls the copy constructor to get a copy of the object you pass as a function object, and then makes another copy (don't know why) and then destroyes the "temporary" objects.
This is documented. The number of copies made is left to the implementation, but generally should be kept to a minimum. If you don't want "pass by value" semantics use a wrapper/adapter such as boost::ref. Bill Kempf