multimap erase

multimap erase

 typedef multimap<CString, CString>::iterator it_authors;
 pair<it_authors, it_authors> pos = theApp.m_chatConetentList.equal_range(strDel);
 if (pos.first!=pos.second)
 {
  theApp.m_chatConetentList.erase(pos.first,pos.second);
 }