lockf, how portable is it? (and an include file matter)

[Stephen R. van den Berg]

Just like I said in the Subject:, is lockf a widely supported library function?

BTW, talking about portability, I checked and it seems that in order
to use the time() library function one has to #include <sys/time.h> only,
*not* time.h.   At least, that is the case in SunOS.  Is this POSIX, or
common?
--
Sincerely,                 berg at marvin.e17.physik.tu-muenchen.de
           Stephen R. van den Berg.
"I code it in 5 min, optimize it in 90 min, because it's so well optimized:
it runs in only 5 min.  Actually, most of the time I optimize programs."