For example, if fcntl returns -1 to signify failure, Perl will massage that into undef. If it returns 0, Perl will use "0 but true" -- which means you can use it either numerically (C-style, expecting 0 to correspond to success) or Booleanifically (Perl-style, expecting 'true' to mean success).

Close enough?

But what is really special about "0 but true" is that it becomes 0 in a numeric context without a warning.

        - tye (but my friends call me "Tye")

But what is really special about "0 but true" is that it becomes 0 in a numeric context without a warning.

ding ding ding ding, that's what I was looking for!

And now for trivia question 2, "why is this so?"

-- Randal L. Schwartz, Perl hacker

Ahh - but it wasn't *in* numeric context....

"false";
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Heheh, you're on to something...

How about the age old paradox:

"This statement is false.";
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Or perhaps even more devilish:

# return true
0 . 0;
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I'd actually write that as:

0 . 0; # sometimes, whitespace DOES matter
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{grin}

-- Randal L. Schwartz, Perl hacker

Well, I fail to see how the string "0 but true" is any more special than "any true value will do".

They're both simply strings that interpolate in a boolean context to true

how about:

0 . "true";
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for something ever so slightly more "evil"...

(c8=

Well, I fail to see how the string "0 but true" is any more special than "any true value will do".

Your failure to see it doesn't mean it's not more special. See other posts in this thread.

Hint: turn on warnings.

-- Randal L. Schwartz, Perl hacker

My current fave is:

# grr...
"Why should version 5.6 make me do this in a module?"
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Of course I like the capital letter "O"; too =)

--
$you = new YOU;
honk() if $you->love(perl)