wc 'Is a directory' output

[Christopher Jordan-Squire]

Hi--I was playing around with using awk on wc output and discovered
that when wc prints "wc: DIR: Is a directory", where DIR is the
appropriate directory name, it doesn't seem to be printing to stdout.
If I redirect the output of, say, wc -l ./* to a text file with '>'
then I don't get the "wc: DIRE: Is a directory" statements. That's
also causing some weird issues when I pipe wc's output to awk.

I was trying to understand how wc prints the "Is a directory" line.
But I haven't been able to figure it out after looking through the
source for 45 minutes. (I'm a very inexperienced C coder, though. So I
could have missed something easy.) Could anyone tell me what wc is
doing and where this shows up in the source?

Thanks,
Chris JS