My only guess as to why it continues is because <FP> actually returns 0 and a newline character.

It does, and a string containing “0\n” is true, not false:

14:26 >perl -we "my $s = qq[0\n]; printf qq[%s\n], ($s ? 'true' : 'fal
+se');"
true

14:31 >

[download]

To see the special behaviour described by ++davido, you can set the $/ variable (the input record separator) to read 1 character at a time, and then try a C-style for-loop (which does not have the special behaviour):

#! perl
use strict;
use warnings;

local $/ = \1;

for ($_ = <DATA>; $_; $_ = <DATA>)
{
    print "<$_>\n";
}

__DATA__
1
0
42

[download]

— the loop terminates on the 0. To get the desired behaviour, change it to:

for ($_ = <DATA>; defined $_; $_ = <DATA>)

[download]

and a little experimentation will show you that this is now equivalent to the special forms:

print "<$_>\n" for <DATA>;

[download]

and

print "<$_>\n" while <DATA>;

[download]

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

In reply to Re: while (<FP>) conditionals by Athanasius
in thread while (<FP>) conditionals by jktstance

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