pipe list open trouble?

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

Hello all,

Can anybody explain why I'm seeing the difference in those pieces of code? I thought these should be identical:

$ perl -e 'open F, @ARGV or die $!' '|-' echo 42
No such file or directory at -e line 1.

$ perl -e 'open F, $ARGV[0],$ARGV[1],$ARGV[2] or die $!' '|-' echo 42
42
[download]

Thank you!

Comment on pipe list open trouble? Download Code

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Re: pipe list open trouble? by salva (Canon) on Sep 30, 2014 at 13:13 UTC
That's a quirk of the `open` built-in: It forces scalar context on its second argument. `open F, @ARGV;` [download] ... is equivalent to ... `open F, scalar(@ARGV);` [download] As a workaround you can use... `my ($mode, @cmd) = @ARGV; open F, $mode, @cmd or die ...;` [download] update: `prototype` shows it: `$ perl -E 'say prototype(\CORE::open)' ;$@` [download]	[reply] [d/l] [select]
Re^2: pipe list open trouble? by LanX (Saint) on Sep 30, 2014 at 14:46 UTC
Good example why the use of `$` prototypes is usually discouraged. :) Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :)}	[reply] [d/l]
Re^3: pipe list open trouble? by salva (Canon) on Sep 30, 2014 at 15:28 UTC
Technically, prototypes are not involved here. The way `open` arguments are parsed is hard-coded inside the Perl grammar and the `prototype(\*CORE::...)` construction is just a facade.	[reply] [d/l] [select]


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