Declaring an array of negative length

Question

What happens in C when you create an array of negative length?

For instance:

int n = -35;

int testArray[n];

for(int i = 0; i < 10; i++)
    test         


        

Answer 1

Undefined behavior, I believe, though don't quote me on that.

This gives the error error: size of array 'testArray' is negative in gcc:

int testArray[-35];

though, as you've seen:

int n = -35;
int testArray[n];

does not give an error even with both -Wall and -W.

However, if you use -pedantic flag, gcc will warn that ISO C90 forbids variable length array.