Judging from the name of your function, performance can’t be that critical to even consider moving parameters to global variables just to save time/space required to pass them as parameters (IO operations like checking files are much-much slower than calling functions and passing values to them). Slices in Go are just small descriptors, something like … Read more
Because it’s a virtual address, not a physical one. Each process gets its own address space (for example, a 32-bit system may allow each process to have its own address space with the full 4G range). It’s the memory management unit that will map virtual addresses to physical ones (and handle things like page faults … Read more
Array is implemented with copy-on-write behaviour – you’ll get it regardless of any compiler optimisations (although of course, optimisations can decrease the number of cases where a copy needs to happen). At a basic level, Array is just a structure that holds a reference to a heap-allocated buffer containing the elements – therefore multiple Array … Read more
Copy on write as the name suggests means no variable is being copied until something is written; as long as not a single byte is changed in the variable passed around, PHP takes care of avoiding unnecesary duplicates automatically and without the need of using explicit references thanks to this mechanism. This article explains in … Read more
I was going to write up my own explanation but this Wikipedia article pretty much sums it up. Here is the basic concept: Copy-on-write (sometimes referred to as “COW”) is an optimization strategy used in computer programming. The fundamental idea is that if multiple callers ask for resources which are initially indistinguishable, you can give … Read more
It’s not allowed, because as per the standard 21.4.1 p6, invalidation of iterators/references is only allowed for — as an argument to any standard library function taking a reference to non-const basic_string as an argument. — Calling non-const member functions, except operator[], at, front, back, begin, rbegin, end, and rend. For a COW string, calling … Read more