Under the covers Perl is calling the stat(2) system call (or your platform's analogue to it). This system call returns a buffer of information containing several items relating to the file it was called on (such as the size, owner, modification and access times, etc.). When you use the special underscore filehandle, you're telling Perl "hey, don't make another call to the OS I just want another value from what you got last time".

In reply to Re: About Special Underscore Filehandle by Fletch
in thread About Special Underscore Filehandle by PerlPhi

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