getpwnam(@

perl5ever has asked for the wisdom of the Perl Monks concerning the following question:

I'm wondering why g1 and g2 don't give the same results:

sub g1 { getpwnam(@_) }
sub g2 { getpwnam($_[0]) }

print "g1: ", g1("root"), "\n";
print "g2: ", g2("root"), "\n";
[download]

Output:

g1: 
g2: rootx00root/root/bin/bash
[download]

Comment on getpwnam(@_) ??? Select or Download Code

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Re: getpwnam(@_) ??? by Fletch (Bishop) on Mar 31, 2011 at 18:21 UTC
getpwnam imposes scalar context on its argument. $ perl -le 'print prototype q{CORE::getpwnam}' $ [download] That means that `@_` is treated as the number of elements `g1` was called with and I doubt you have a user named "1" on your system. The cake is a lie. The cake is a lie. The cake is a lie.	[reply] [d/l] [select]
Re: getpwnam(@_) ??? by ikegami (Patriarch) on Mar 31, 2011 at 18:19 UTC
It has a prototype that causes the argument to be evaluated in scalar context. $ perl -E'say prototype("CORE::getpwnam")' $ [download]	[reply] [d/l]
Re: getpwnam(@_) ??? by wind (Priest) on Mar 31, 2011 at 18:21 UTC
getpwnam assumes a scalar, so you're array is being turned into the array count. `sub g1 { getpwnam(@_) } # equivalent to. sub g1 { getpwnam(scalar @_) }` [download]	[reply] [d/l]