Re: Code reviews [Was: FWTK and smap/smapd]

[Joseph S D Yao <jsdy () center osis gov>]

On Wed, Jul 24, 2002 at 02:35:24AM +1000, Darren Reed wrote:
> In some email I received from Joseph S D Yao, sie wrote:
> > Oh, geez, shouldn't everyone have written [something like] this?
>
> No...
>
> Your parameters are wrong, for a start :-)
> They were "char *buf" and "unsigned int buflen".
>
> > register char *cp = buf;

Look a little harder.  "buf" is the same as "buf".  I don't know about
"buflen", but I will plead nolo contendere to "buflen" if you plead
guilty to nitpicking.  ;-)

> > register int i, count = n;
> >
> > for (;;) {
> >     i = write(fd, cp, count);
> >     if (i < 0) {
> >             perror("...");
> >             fprintf(stderr, ...);
> >             break;
> >     }
> >     count -= i;
> >     if (count <= 0) /* yes, should never be <, optionally fuss */
> >             break;
> >     cp += i;
> >     if (i == 0 {
> >             sleep(1);
> >             /* should probably count and break if too many */
> >     }
> > }

> You're using a "for (;;)" where it isn't required - should be
> "while (count != 0)", the "if (count <= 0) ..." should be nuked from orbit.

Hmmm.  I should have started the whole thing with "if (n == 0) return;"
as we are not guaranteed that it is non-zero.  Otherwise, I would argue
that if "Say What You Mean" [Joe's First Law of Software Engineering]
is uppermost in your mind, then the "for (;;)" and "if (count <= 0)"
are exactly where they should be.  Once you have written all the bytes,
why execute the rest of the code?

> Hanlding write() returning 0 bytes, is, umm, bizarre ?  Carson never
> said anything about non-blocking I/O but apparently it was implied.
> That's a failure in the specification, I say :-)

No.  It is always possible for a write() to return 0.  If it seems
bizarre, it is because PEOPLE DON'T HANDLE UNEXPECTED CASES PROPERLY.

> Carson wanted specific handling of things like EINTR...

And I did that off the top of my head without the specs in front of me,
so I missed that.

You missed the parenthesis where I didn't press the key hard enough so
it was too faint for you to see.  ;-)

-- 
Joe Yao                         jsdy () center osis gov - Joseph S. D. Yao
OSIS Center Systems Support                                     EMT-B
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