Re: Deleting an element from a list in a loop

From:
"Andrew Chalk" <achalk@magnacartasoftware.com>
Newsgroups:
microsoft.public.vc.stl
Date:
Wed, 30 Aug 2006 01:51:36 -0500
Message-ID:
<#pYcMDAzGHA.480@TK2MSFTNGP06.phx.gbl>
Thanks!
"Doug Harrison [MVP]" <dsh@mvps.org> wrote in message
news:uq8af29f0antihmum7pvjclm9jsed5etpl@4ax.com...

On Wed, 30 Aug 2006 00:09:09 -0500, "Andrew Chalk"
<achalk@magnacartasoftware.com> wrote:

Will deleting an element from a list while iterating through a loop mess
up
the internal pointers? I am thinking of a construct such as this where I
call erase() in the loop:

for (;it != m_list.end(); it++) {

   if ((*it)->ThreadFinished() == true) {

       ...DO STUFF

       m_list.erase(it); // delete the element from the list

       // Do we need to break out of the loop here?

   }

}


Erasing a list element invalidates iterators, references, and pointers to
the item erased, so you need to structure your loop like this:

while (it != m_list.end())
{
  if ((*it)->ThreadFinished()) // Don't compare against true or false
  {
     it = m_list.erase(it);
     // or m_list.erase(it++);
  }
  else
     ++it;
}

--
Doug Harrison
Visual C++ MVP

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