defer.c

void example()
{
    A *a; 
    B *b; 

    defer_start();
    defer(puts, "bye");

    a = a_new();
    if (! a){
        defer_end();
    }
    defer(a_delete, a);
	
    b = b_new();
    if (! b){
        defer_end();
    }
    defer(b_delete, b);
	
    use_b(b);
    defer_end();	
}