CODEWITHSUNDEEP
c++listsegmentation-fault
Robin
Robin

Reputation: 737

Segmentation fault from pop_front() in C++

My problem is that I am getting a segmentation fault that occurs after I call "processList.pop_front()". If I comment out "processList.pop_front()", a segmentation then occurs during the second iteration of the outermost for loop, after a tt.pop_front() call, after that inner for loop has gone through almost 5000 iterations. I can't see what the problem is. Any thoughts?

loopLimit = processList.size();

for(int i = 0; i < loopLimit; i++)
{
    tempProcess = processList.front();
    tt = tempProcess.memAccesses;
    cout << "process number " << i << "\n";

    while(!tt.empty())
    {
        t = tt.front();
        tt.pop_front();
        cout << "from processlist: " << t.instrType << "  " << t.instrAddr << "\n";
    }

    if(!processList.empty())
    {
        cout << "size is now: " << processList.size() << "\n";
        processList.pop_front();
    }

}

Upvotes: 0

Views: 1689

Answers (1)

Vili
Vili

Reputation: 21

I have a similar problem and I solved it by adding an invalid value to the deque: 

loopLimit = processList.size();

for(int i = 0; i < loopLimit; i++)
{
    tempProcess = processList.front();
    tt = tempProcess.memAccesses;
    cout << "process number " << i << "\n";

    tt.push_back(-1);  //I guess you don't have a -1 type, so you wont have colisions
    while( tt.front()!=-1)
    {
        t = tt.front();
        tt.pop_front();
        cout << "from processlist: " << t.instrType << "  " << t.instrAddr << "\n";
    }

    if(!processList.empty())


    {
        cout << "size is now: " << processList.size() << "\n";
        processList.pop_front();
    }

}

Probably you will have to adapt it a bit. Is not a very nice solution, but it works.

Upvotes: 2

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