If I have a scalar ref holding on to a big string, and take its length, will dereferencing it into length cause the string to be copied? I'm hoping since length is a builtin, it would not. 
 
  my $x = \" VERY VERY BIG STRING .....";
  my $len = length( $$x );

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If it were a sub, however, it would be 
     sub foo { my $s = shift; my $r = \$s; print "FOO ($r)\n" } 
     my $X = "SOMESTRING"; 
     my $O = \$X; 
     my $R = \$X; 
     print "NOTFOO ($R,$O)\n";                                        
+   
     foo( $$R );

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outputs 
NOTFOO (SCALAR(0x9393f8),SCALAR(0x9393f8))
FOO (SCALAR(0x9394a0))

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EDIT, after some help from my friends One delightful thing I learned is that the @_ elements are _not_ copies. A sub does not have to copy. 
     sub foo { my $r = \$_[0]; print "FOO ($r)\n" } 
     my $X = "SOMESTRING"; 
     my $O = \$X; 
     my $R = \$X; 
     print "NOTFOO ($R,$O)\n";                                        
+   
     foo( $$R );

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outputs 
NOTFOO (SCALAR(0x1ac23e8),SCALAR(0x1ac23e8))
FOO (SCALAR(0x1ac23e8))

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Original content restored below by GrandFather for reference.

If I have a scalar ref holding on to a big string, and take its length, will dereferencing it into length cause the string to be copied?

 my $x = \" VERY VERY BIG STRING ....."; my $len = length( $$x );

In reply to scalar reference and length by coyocanid

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