What is a neat way of breaking out of many for loops at once?

Question

Suppose I need to break out of three or four nested for loops at once at the occurence of some event inside the innermost loop. What is a neat way of doing that?

Answer 1

goto. This is one of the very few places where goto is the appropriate tool, and is usually the argument presented why goto isn't complete evil.

Sometimes, though, I do this:

void foo() {
    bar_t *b = make_bar();
    foo_helper(bar);
    free_bar(b);
}

void foo_helper(bar_t *b) {
    int i,j;
    for (i=0; i < imax; i++) {
        for (j=0; j < jmax; j++) {
            if (uhoh(i, j) {
                return;
            }
        }
    }
}

The idea is that I get a guaranteed free of bar, plus I get a clean two-level break out of the switch via return.