"Error" in libPW

[Guy Harris]

> The problem is that almost none of libPW seems to be documented.
> The only routines I've found with documentation are the regular
> expression routines (regcmp(3X)), and this manual page only mentions
> libPW in passing.
> 
> Does anyone know if there is other documentation available for this
> stuff?

I think libPW is considered obsolete cruft; I have never seen any AT&T
documentation for it in any (generally distributed) release subsequent to
PWB/UNIX 1.0.  The regular expression stuff is definitely cruft; use <regexp.h>
instead (it's what the S5 "ed", "sed", "grep", and "pg" use).