GOTO still considered harmful? [closed]

Answer 1

Go To can provide a sort of stand-in for "real" exception handling in certain cases. Consider:

ptr = malloc(size);
if (!ptr) goto label_fail;
bytes_in = read(f_in,ptr,size);
if (bytes_in=<0) goto label_fail;
bytes_out = write(f_out,ptr,bytes_in);
if (bytes_out != bytes_in) goto label_fail;

Obviously this code was simplified to take up less space, so don't get too hung up on the details. But consider an alternative I've seen all too many times in production code by coders going to absurd lengths to avoid using goto:

success=false;
do {
    ptr = malloc(size);
    if (!ptr) break;
    bytes_in = read(f_in,ptr,size);
    if (count=<0) break;
    bytes_out = write(f_out,ptr,bytes_in);
    if (bytes_out != bytes_in) break;
    success = true;
} while (false);

Now functionally this code does the exact same thing. In fact, the code generated by the compiler is nearly identical. However, in the programmer's zeal to appease Nogoto (the dreaded god of academic rebuke), this programmer has completely broken the underlying idiom that the while loop represents, and did a real number on the readability of the code. This is not better.

So, the moral of the story is, if you find yourself resorting to something really stupid in order to avoid using goto, then don't.