'what' doesn't use perror to print open errors, Sys V/3.0

Tue May 2 13:30:05 AEST 1989

>The perror() function has been SVID level 2 since 1985, which
>means that it is no longer guaranteed to be supported after 1988.
>I believe it will be in the next SVID (Issue 3), but it may go
>away after that.

And then again, it may not.  "perror" is in the pANS for C, so even if
AT&T rips it out of the SVID, vendors will probably have to provide it
anyway in their C implementations.