Re: Restoring the magic to the _ filehandle in Perl 5.8.9

The statement: 'The code below, in Perl 5.8.8 and 5.10.9 prints 1\n three times' is incorrect and confusing... I'm guessing you are confusing the different versions of perl...

Running 'the code below':

Perl version: 5.006

Use of uninitialized value in print at t.pl line 24.

Undefined subroutine &main::_ called at t.pl line 28.

Perl version: 5.008

Use of -l on filehandle _ at t.pl line 24.
Use of uninitialized value in print at t.pl line 24.

Undefined subroutine &main::_ called at t.pl line 28.

Perl version: 5.008008

Use of -l on filehandle _ at t.pl line 24.
Use of uninitialized value in print at t.pl line 24.

Undefined subroutine &main::_ called at t.pl line 28.

Perl version: 5.008009

Use of -l on filehandle _ at t.pl line 24.
Use of uninitialized value in print at t.pl line 24.

Undefined subroutine &main::_ called at t.pl line 28.

Perl version: 5.010000
```
1
1
1
```
Perl version: 5.011003
```
1
1
1
```

Comment on Re: Restoring the magic to the _ filehandle in Perl 5.8.9

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Re^2: Restoring the magic to the _ filehandle in Perl 5.8.9 by ikegami (Patriarch) on Jan 27, 2010 at 23:11 UTC
And the reason is that 5.10 doesn't consider "`_`" in "`-X _`" a function call. >perl588\bin\perl -MO=Concise -e"sub _; -l _" 7 <@> leave[1 ref] vKP/REFC ->(end) 1 <0> enter ->2 2 <;> nextstate(main 1 -e:1) v ->3 6 <1> ftlink vK/1 ->7 5 <1> entersub[t2] sKS/TARG,1 ->6 - <1> ex-list sK ->5 3 <0> pushmark s ->4 - <1> ex-rv2cv sK/128 ->- 4 <#> gv[_] s ->5 -e syntax OK >perl589\bin\perl -MO=Concise -e"sub _; -l _" 7 <@> leave[1 ref] vKP/REFC ->(end) 1 <0> enter ->2 2 <;> nextstate(main 1 -e:1) v ->3 6 <1> ftlink vK/1 ->7 5 <1> entersub[t2] sKS/TARG,1 ->6 - <1> ex-list sK ->5 3 <0> pushmark s ->4 - <1> ex-rv2cv sK/128 ->- 4 <#> gv[_] s ->5 -e syntax OK >perl5100\bin\perl -MO=Concise -e"sub _; -l _" 4 <@> leave[1 ref] vKP/REFC ->(end) 1 <0> enter ->2 2 <;> nextstate(main 1 -e:1) v:{ ->3 3 <#> ftlink[*_] vR ->4 -e syntax OK [download]	[reply] [d/l] [select]

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Re^2: Restoring the magic to the _ filehandle in Perl 5.8.9
by ikegami (Patriarch) on Jan 27, 2010 at 23:11 UTC

_

-X _

>perl588\bin\perl -MO=Concise -e"sub _; -l _"
7  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
6     <1> ftlink vK/1 ->7
5        <1> entersub[t2] sKS/TARG,1 ->6
-           <1> ex-list sK ->5
3              <0> pushmark s ->4
-              <1> ex-rv2cv sK/128 ->-
4                 <#> gv[*_] s ->5
-e syntax OK

>perl589\bin\perl -MO=Concise -e"sub _; -l _"
7  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
6     <1> ftlink vK/1 ->7
5        <1> entersub[t2] sKS/TARG,1 ->6
-           <1> ex-list sK ->5
3              <0> pushmark s ->4
-              <1> ex-rv2cv sK/128 ->-
4                 <#> gv[*_] s ->5
-e syntax OK

>perl5100\bin\perl -MO=Concise -e"sub _; -l _"
4  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
3     <#> ftlink[*_] vR ->4
-e syntax OK
[download]

[reply]
[d/l]
[select]