Re: commenting no-op lines lead to wrong results

From:

Tom Widmer <tom_usenet@hotmail.com>

Newsgroups:

comp.lang.c++

Date:

Mon, 26 Jun 2006 14:30:33 +0100

Message-ID:

<e7on9i$n11$1@nntp.aioe.org>

julien.durand.1981@gmail.com wrote:

hi,

I'm just having a weird problem that I can't explain by myself and
would appreciate someone else's view on this piece of code (used in a
JNI project). Basically if I remove some no-op lines the compiled
library does not produce a valid result (does not load the file). I
suspect that this can come from an error in the compile/linking chain
but can't spot it... Has anyone already face something like that ? :

void Store::load(const string& filename){
    ifstream is(filename.c_str(), ios::binary | ios::in);
    DataInputStream dis(&is);
    Vector v;
    bool test;
    while(dis>>v){
        addVector(v);

        //no-op!!!!!!
        test=false;
    }
    is.close();

    int i=0;

        //no-op!!!!!!!
    cout<<dis<<" "<<i<<" "<<" "<<endl;
}

Most often this will be due to a bug in your code, such as stack
corruption, which is hidden by the presence of the no-op lines. In this
case, are you sure that the Vector class is correct? And the addVector
function? What happens when you step through it with a debugger?

Of course, it could be a compiler bug, but that's much less likely.

Tom