FP Bughunting : Array index out of bounds, cannot determine that i is less than 2

[dp11]

With head and this

int main()
{   
    int D[] = {1,2,3};  
    int j = (sizeof(D) / sizeof(E))-1;
    int a;
    int i;
    for(i=0;i< j ; i++)
            a = D[i];
}

and this command line

./cppcheck --bug-hunting ../FP2.c

I get :

../FP2.c:9:10: error: Array index out of bounds, cannot determine that i is less than 3 [bughuntingArrayIndexOutOfBounds]
   a = D[i];
         ^
../FP2.c:9:10: error: Array index out of bounds, cannot determine that i is not negative [bughuntingArrayIndexNegative]
   a = D[i];
         ^

[dp11]

could someone check I'm not going made i.e cppcheck should know i is positive and the bounds of the loop.

[Daniel Marjamäki]

thanks! I have created ticket https://trac.cppcheck.net/ticket/10757

[dp11]

Thanks, just for my interest does this mean that with out bug hunting enabled there is a possibility of false negatives in normal operation ?

[Daniel Marjamäki]

No. Bug hunting uses a totally separated and very different value flow analysis. It was written from scratch to be "soundy".

[dp11]

Thanks for the extra info.