It's much lower level than that. The OS knows whether or not anything has tried to write to that part of the filesystem, so if nothing has, it knows its cache of the file is still good. Perl is still compiling every time -- the opcode tree of your program is not stored anywhere between calls to it -- but the actual file access that is sped up.

In reply to Re^3: does perl cache between invocations? by perrin
in thread does perl cache between invocations? by punkish

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