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Date: Tue, 30 Aug 2005 13:01:00 -0000
From: "relf at os2 dot ru" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050830125045.23633.relf@os2.ru>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug c++/23633] New: map::insert() invalidates reverse_iterators
X-Bugzilla-Reason: CC
X-SW-Source: 2005-08/txt/msg03442.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

gcc (GCC) 4.0.2 20050821 (prerelease) (Debian 4.0.1-6)

In the following program inserting a new element into a map (i.e., M[2]=2)
invalidates an existing map::reverse_iterator im2. Before this insertion the
reverse_iterator im2 points to the pair (1,1), and after the insertion it
becomes erroneously pointing to the newly inserted pair (2,2).
There is no such problem with map::iterator m1.

Sample output:

before insertion:
im1->first = 1
im2->first = 1
after insertion:
im1->first = 1
im2->first = 2


#include <map>
#include <iostream>
using namespace std;

int main() {
    map<int,int> M;
    M[1] = 1;
    map<int,int>::iterator im1=M.begin();
    map<int,int>::reverse_iterator im2=M.rbegin();

    cout << "before insertion:" << endl;
    cout << "im1->first = " << im1->first << endl;
    cout << "im2->first = " << im2->first << endl;

    M[2] = 2;

    cout << "after insertion:" << endl;
    cout << "im1->first = " << im1->first << endl;
    cout << "im2->first = " << im2->first << endl;

    return 0;
}

-- 
           Summary: map::insert() invalidates reverse_iterators
           Product: gcc
           Version: 4.0.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: relf at os2 dot ru
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23633