Need to know on the differnece between the usgae of $st_mode and $'st

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Need to know on the differnece between the usgae of $st_mode and $'st_mode what does the single quote refer to by ikegami (Patriarch) on Mar 25, 2010 at 05:45 UTC
`$'var` is an obsolete notation for `$::var`, which is also known as `$main::var`	[reply] [d/l] [select]
Re^2: Need to know on the differnece between the usgae of $st_mode and $'st_mode what does the single quote refer to by aufflick (Deacon) on Mar 25, 2010 at 05:52 UTC
Used to good effect by Acme modules such as Acme::Can't, Acme::Isn't and Acme::Don't :)	[reply]
Re^3: Need to know on the differnece between the usgae of $st_mode and $'st_mode what does the single quote refer to by eyepopslikeamosquito (Archbishop) on Mar 25, 2010 at 20:20 UTC
For CPAN historians, this trick was also used by what I believe is the first CPAN joke module (D'oh), released several years before the Acme namespace was invented by TheDamian in 2001: D'oh by C.Nandor I've also seen it employed in Perl Poetry, obfu and even golf (to improve the tie breaker by replacing `sub SomeSub{...}` with `sub'SomeSub{...}`).	[reply] [d/l] [select]
Re: Need to know on the differnece between the usgae of $st_mode and $'st_mode what does the single quote refer to by Anonymous Monk on Mar 26, 2010 at 12:04 UTC
So is this the same case with &' and @' as well to access global function and global array respectively?	[reply]
Re^2: Need to know on the differnece between the usgae of $st_mode and $'st_mode what does the single quote refer to by Anonymous Monk on Mar 26, 2010 at 12:13 UTC
No. ' is the name of the variable, and because you don't declare it, it is global, and because the current package is main, they are &main::' and @main::' respectively `$ perl -le"print \@', \@{qq!main::'!}" ARRAY(0x979ff4)ARRAY(0x979ff4) $ perl -le"print &'" Undefined subroutine &main::' called at -e line 1.` [download]	[reply] [d/l]