libstdc++/8356: Operator precedence-- dereferencing an incremented iterator

libstdc++/8356: Operator precedence-- dereferencing an incremented iterator

[jddahl]

>Number:         8356
>Category:       libstdc++
>Synopsis:       Operator precedence-- dereferencing an incremented iterator
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 25 09:36:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     jddahl@micron.com
>Release:        GCC 3.2
>Organization:
>Environment:

>Description:
#include <set>
#include <string>
#include <iostream>

using namespace::std;

int main( )
{
  set<string> mySet;
  set<string>::const_iterator iter;

  mySet.insert( "This" );
  mySet.insert( "is" );
  mySet.insert( "mySet" );
  iter = mySet.begin( );
  cout << *iter++ << " " << *iter++ << " " << *iter << endl;
  iter = mySet.begin( );
  cout << *iter++ << " " << *iter++ << " " << *iter++ << endl;
  iter = mySet.begin( );
  cout << *iter << " " << *(++iter) << " " << *(++iter) << endl;

  //WORKAROUND
  iter = mySet.begin( );
  cout << *iter << " ";
  iter++;
  cout << *iter << " ";
  iter++;
  cout << *iter << endl;
}

OUTPUT:
is This This
mySet is This
mySet mySet is
This is mySet
>How-To-Repeat:
Compile submitted code and run.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:

Re: libstdc++/8356: Operator precedence-- dereferencing an incremented iterator

[bangerth]

Synopsis: Operator precedence-- dereferencing an incremented iterator

State-Changed-From-To: open->closed
State-Changed-By: bangerth
State-Changed-When: Fri Oct 25 09:57:54 2002
State-Changed-Why:
    You are modifying the iterator more than once within one
    statement. Since the order of modification and evaluation of
    the iterator is not specified, you are invoking undefined
    behavior.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8356