instability in Berkeley versus AT&T releases (really index)

[John Mashey]

Guy Harris writes (onto long sequence of articles):
> > > * Don't flame me if the index/strchr difference isn't an example of NIH --
> > >   I haven't used V5 much...
> 
> Furthermore, the index/strchr difference is probably not an example of NIH
> in the way the original poster thought.  *Both* routines are products of
> AT&T - the routine was called "index" in V7 and "strchr" in System III.  At
> what point it was renamed, I dunno.  The S3 documentation comes with a
> description of changes between S3 and some unspecified earlier version of
> UNIX.  One of the changes was that "strcpyn" was renamed "strncpy".  This
> predates V7, since it was called "strncpy" there as well.

0) As usual, Guy has pretty good model of the history, minor details:

1) index->strchr happened in UNIX/TS 1.0 (in some sense, System I of the System
V sequence). My 1.0 manual reads November 78; as  I recall, this particular
change happened fairly early in the packaging effort that was trying to
get Edition 7 (late, but not released), PWB/UNIX 1.2, and some USG G3
UNIX all back together.

2) strcpyn ->strncpy happened at the same time, early 78. The rename
was because some non-UNIX systems (GCOS, I think) took only the first
6 characters, so that strcpy and strcpyn conflicted, a clearly bad thing.

3) In general, it is unwise to EVER label something as NIH unless you know
for a fact that it is NIH.  There are more weird reasons for things being
different in different UNIX versions than you would ever believe; only a few
of them are NIH; it is always best to ask why things are different.
-- 
-john mashey
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