Re: [9fans] gcc/plan9

[Geoff Collyer <geoff@collyer.net>]

Testing that *scanf found exactly the number of items you expected is
usually the right thing to do.  scanf and fscanf can return EOF (-1),
so a test against zero will usually be inappropriate.
So the last example you gave,

	if (sscanf(str+(*pos),"%d",&tag)==1)

should be used everywhere, including linux (and tag should be an int,
not a long nor a short).

strings.h is an archaism and shouldn't be needed nor included.  All
ANSI C implementations (hosted ones, anyway) must provide string.h,
and it's been 13 years since the first ANSI C standard, so everybody
really ought to have string.h by now.

GNU configure and much GNU software go out of their way to support
aged or deficient C implementations.  I think it's no longer worth
worrying about pre-ANSI implementations, except for amusement (e.g.,
running V7 on a PDP-11 simulator).  As for broken implementations,
with C News, we found that it was generally better not to contort our
code to accommodate bugs in somebody's C implementation, but to
publish the bug (perhaps including a pointer to the section of the
current C standard that forbids the erroneous behaviour), a test case
to demonstrate it, and a workaround, and to distribute the whole
bundle widely.  Once a vendor realises that it really is his bug and
the customers know it and demand a fix, he tends to fix the bug pretty
quickly.  We found astonishing bugs in production C implementations,
some of which had been around for a long time, and I think helped to
get them fixed.