Re: Dualvars besides $!

This post is wrong.

Whether the docs are correct or not depends on the version of Perl.

perl -MDevel::Peek -e'$!=1; print("$!\n"); Dump($!);'
[download]

5.8.9:

...
  FLAGS = (GMG,SMG,pNOK,pPOK)
...
[download]

No public values. Not a dualvar.

5.18.1:

...
  FLAGS = (GMG,SMG,NOK,POK,pNOK,pPOK)
...
[download]

Two public values (NOK = has NV = has floating point number, POK = has PV = has string). Dualvar.

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Re^2: Dualvars besides $! by ikegami (Patriarch) on Jan 27, 2014 at 20:01 UTC
The latest `Scalar::Util::isdual` considers `FLAGS = (GMG,SMG,pNOK,pPOK)` to be a dualvar. (No idea about earlier versions, but I suspect it's the same.) The docs are wrong. The following returns `1` for both 5.8.9 and 5.18.1, while the docs say it returns false: `perl -MScalar::Util=isdual -MDevel::Peek \ -e'$!=1; print("$!\n"); print(isdual($!)?1:0,"\n"); Dump($!);'` [download] Nit: `$!` is magical (like tied variables), but it's not a tied variable like the docs say.	[reply] [d/l] [select]

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Re^2: Dualvars besides $!
by ikegami (Patriarch) on Jan 27, 2014 at 20:01 UTC

The latest Scalar::Util::isdual considers FLAGS = (GMG,SMG,pNOK,pPOK) to be a dualvar. (No idea about earlier versions, but I suspect it's the same.) The docs are wrong. The following returns 1 for both 5.8.9 and 5.18.1, while the docs say it returns false:

perl -MScalar::Util=isdual -MDevel::Peek \
   -e'$!=1; print("$!\n"); print(isdual($!)?1:0,"\n"); Dump($!);'
[download]

Nit: $! is magical (like tied variables), but it's not a tied variable like the docs say.

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