> This would work without the -f; note that which(1) is required to use
 > the user's .cshrc.

Why?  Not only is this dead wrong for non-csh users, I would argue that
it is wrong for csh users as well.  It appears that the csh maintainer(s)
agree with me; note that the csh which builtin does NOT source .cshrc,
so it's even inconsistent with that one now.  I would argue that
/usr/bin/which could actually be removed entirely, since there's no
point in having the current implementation there when csh users will
always use the built-in variant.

 > A C program is no good because it doesn't use .cshrc, as specified by
 > which(1).

Well, I now also have a man page change, that specifies the actual
behaviour of the csh builtin and my C program.  I agree that the
specification and implementation should match.  But when the
specification is wrong, it should be changed.

What if .cshrc doesn't even exist?  I never create, and usually delete
entirely if it existed, any .cshrc on my accounts.

 > In order to do so it would have to parse .cshrc, at which
 > point you might as well have used csh in the first place.

What is the reason that you want .cshrc parsed?  This is wrong, has
been wrong for a long time, and will only become even more wrong as
time passes.  Since I never used 3.0BSD I don't know if it was a
good idea at that time; but I'm convinced that it's long past the
time when it should have been changed.

   -  Arne H. J.