Perl is at the mercy of your machine's definitions of various operations such as type casting, atof() and sprintf().
If your stdio requires an seek or eof between reads and writes on a particular stream, so does perl. (This doesn't apply to sysread() and syswrite().)
While none of the built-in data types have any arbitrary size limits (apart from memory size), there are still a few arbitrary limits: a given identifier may not be longer than 255 characters, and no component of your PATH may be longer than 255 if you use -S. A regular expression may not compile to more than 32767 bytes internally.
actually stands for Pathologically Eclectic Rubbish Lister, but don't tell
anyone I said that.