Question about coreutils 'cp' - does it check target file after copying?

Hello,

May be it's already answered question, but I couldn't find anything
about that.

Does the GNU coreutils 'cp' utility guarantee that the target file
after copying is the same as the source one?

If it doesn't then I'll need to make my own diff-ing or checksums
verifying, right? Or maybe, all the copying is implemented via 100%-
reliable low-level calls, so all the checking I'm talking about is
redundant?

Thanks
Alex