Don't place all cleanup actions at the end of a function and `goto exit`

Reason

goto is error-prone. This technique is a pre-exception technique for RAII-like resource and error handling.

Example, bad

void do_something(int n)
{
    if (n < 100) goto exit;
    // ...
    int* p = (int*) malloc(n);
    // ...
    if (some_error) goto exit;
    // ...
exit:
    free(p);
}

and spot the bug.

Alternative

• Use exceptions and RAII
• for non-RAII resources, use finally.