Re^2: How do I make the garbage collector throw an exception when it fails to auto-close a filehandle?

[Aristotle]

in reply to Re: How do I make the garbage collector throw an exception when it fails to auto-close a filehandle?
in thread How do I make the garbage collector throw an exception when it fails to auto-close a filehandle?

In my system, the final string on STDERR gets printed when the close above is commented; uncommenting the close triggers the fatal error:

And that’s exactly the point: when you have an explicit close, you can make it throw an exception; when you omit the close, the error is silent. But I want to omit the close and still get an exception. Fatal won’t help me there.

Thanks for the pointer about the loop device though! All I can say in retrospect is, d’uh. However, Linux has an easier way, mentioned by Zaxo in the old thread from gaal: there’s a /dev/full device where writing always fails with ENOSPC.

[BrowserUk]

Won't the /dev/full device fail when you try to write to it long before you get to close it?

[Aristotle]

No…

$ perl -MFatal=open,close,syswrite
-e'open $fh,">/dev/full"; syswrite $fh, 1; close $fh'
Can't syswrite(GLOB(0x8130c24), 1): No space left on device at (eval 3) line 3
	main::__ANON__('GLOB(0x8130c24)') called at -e line 1
$ perl -MFatal=open,close
-e'open $fh,">/dev/full"; print { $fh } 1 or die "$!\n"; close $fh'
Can't close(GLOB(0x8130c24)): No space left on device at (eval 2) line 3
	main::__ANON__('GLOB(0x8130c24)') called at -e line 1

… not with buffered I/O.

[polettix]

Oh, I misunderstood that you didn't know for sure about Fatal's behaviour:

In the simplest case, use Fatal qw( :void close ); would work for this, but I strongly doubt it, and in any case I can’t think of a good way to purposefully trigger a close failure in order to test it.

And yes... the loop device rocks :)