Re: matching against failed readline doesn't warn?

I think that you can rule out the regular expression engine from being a key part of this oddity. The following pair shows the same behaviour:

perl -we'open FOO, "/dev/null";$x=<FOO>; print scalar $x'
perl -we'open FOO, "/dev/null"; print <FOO>'
[download]

And it isn't just print either:

perl -we'open FOO, "/dev/null"; $x=<FOO>; print $x+2'
perl -we'open FOO, "/dev/null"; $x=2+<FOO>; print $x'
[download]

demonstrates the same oddity. However:

perl -we'open FOO, "/dev/null"; print defined <FOO>'
[download]

notices that the value is undef.

UPDATE: Fixed the scalar issue that both Abigail-II and ysth pointed out to me. (It didn't make a difference in the warning behaviour.)

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Re: matching against failed readline doesn't warn? by Abigail-II (Bishop) on Apr 08, 2004 at 09:14 UTC
`perl -we'open FOO, "/dev/null"; print <FOO>'` [download] This one has `<FOO>` in list context, so an empty list is returned. No warnings when printing an empty list isn't to be taken as a surprise. Abigail	[reply] [d/l] [select]