You are getting different results, because you are using strict & warnings -- neither of which are enabled in the original sample code in the book.... 

foreach $symname (sort keys %main::) {
    local *sym = $main::{$symname};
    print "\$$symname is defined\n" if defined $sym;
    print "\@$symname is nonnull\n" if         @sym;
    print "\%$symname is nonnull\n" if         %sym;
}

[download]
hossman@slate:~/tmp/9780596004927/programming_perl_examples [master] $
+ perl -E "say $^V"
v5.26.1

[download]
hossman@slate:~/tmp/9780596004927/programming_perl_examples [master] $
+ perl ./program_listings/ch10/ch10.002.pl
 is defined
$ is defined
$" is defined
$/ is defined
$0 is defined
$@ is defined
%CORE:: is nonnull
%DynaLoader:: is nonnull
%ENV is nonnull
@INC is nonnull
%IO:: is nonnull
%Internals:: is nonnull
%PerlIO:: is nonnull
%Regexp:: is nonnull
%UNIVERSAL:: is nonnull
%constant:: is nonnull
%main:: is nonnull
%mro:: is nonnull
%re:: is nonnull
$symname is defined
%utf8:: is nonnull
%version:: is nonnull

[download]
hossman@slate:~/tmp/9780596004927/programming_perl_examples [master] $
+ perl -Mwarnings -Mstrict ./program_listings/ch10/ch10.002.pl
Variable "$sym" is not imported at ./program_listings/ch10/ch10.002.pl
+ line 3.
Variable "@sym" is not imported at ./program_listings/ch10/ch10.002.pl
+ line 4.
Variable "%sym" is not imported at ./program_listings/ch10/ch10.002.pl
+ line 5.
Global symbol "$symname" requires explicit package name (did you forge
+t to declare "my $symname"?) at ./program_listings/ch10/ch10.002.pl l
+ine 1.
Global symbol "$symname" requires explicit package name (did you forge
+t to declare "my $symname"?) at ./program_listings/ch10/ch10.002.pl l
+ine 2.
Global symbol "$symname" requires explicit package name (did you forge
+t to declare "my $symname"?) at ./program_listings/ch10/ch10.002.pl l
+ine 3.
Global symbol "$sym" requires explicit package name (did you forget to
+ declare "my $sym"?) at ./program_listings/ch10/ch10.002.pl line 3.
Global symbol "$symname" requires explicit package name (did you forge
+t to declare "my $symname"?) at ./program_listings/ch10/ch10.002.pl l
+ine 4.
Global symbol "@sym" requires explicit package name (did you forget to
+ declare "my @sym"?) at ./program_listings/ch10/ch10.002.pl line 4.
Global symbol "$symname" requires explicit package name (did you forge
+t to declare "my $symname"?) at ./program_listings/ch10/ch10.002.pl l
+ine 5.
Global symbol "%sym" requires explicit package name (did you forget to
+ declare "my %sym"?) at ./program_listings/ch10/ch10.002.pl line 5.
Execution of ./program_listings/ch10/ch10.002.pl aborted due to compil
+ation errors.

[download]

In reply to Re^3: Interrogating stashes - Camel example doesn't work? by hossman
in thread Interrogating stashes - Camel example doesn't work? by Intrepid

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