C : stack memory, goto and “jump into scope of identifier with variably modified type”,

Question

I found that this refuses to compile :

int test_alloc_stack(int size){
    if(0) goto error; // same issue whatever conditional is used
    int apply[size];
         


        

Answer 1

Your goto makes you skip the line that allocates apply (at runtime).

You can solve the problem in one of four ways:

1: Rewrite your code so you don't use goto.

2: Move the declaration of apply to before the goto.

3: Change the scope so that error: is outside the scope of apply:

int test_alloc_stack(int size){
    if(0) goto error; // same issue whatever conditional is used
    {
        int apply[size];
        give_values(apply,size);
        return 1;
    }
    error:
        return 0;
}

4: Change the variable declaration so its size can be determined at compile-time.