[OPEN-ILS-DEV] C nits: invalid conversion specification

[Mike Rylander]

On 5/7/07, Mike Rylander <mrylander at gmail.com> wrote:
> I (or Bill) will be fixing this in HEAD later today, which will put it
> in line for 1.2 as soon as that happens.  Opinions on the criticality
> of backporting to the 1.0 branch?

s/today/this week/

All done. Thanks, guys!

--miker

>
> --miker
>
> On 5/7/07, Joe Atzberger <atzberger at mecdc.org> wrote:
> > Perl accepts it inasmuch as it doesn't consider it an error (even under warnings and strict).  The typical error message
> > would be (for example, with %j):
> >         Invalid conversion in printf: "%j"
> >
> > I agree there doesn't seem to be any reason to use "%lf" in perl either, since apparently all floating point formatting
> > gets handed off to the C sprintf.
> >
> > --Joe
> >
> > Scott McKellar wrote:
> > > What is your basis for saying that Perl accepts "%lf" for printf
> > > and sprintf?
> > >
> > > I looked at the link you provided, and I looked in the camel book
> > > (which has much of the same verbiage), and I don't see any indication
> > > that "%lf" is valid in Perl.
> > >
> > > Given that Perl relies on the C library to format floating point
> > > numbers, one of three things must be happening:
> > >
> > > 1. Perl silently removes the extraneous 'l' before passing the
> > > conversion specification to the C library, or:
> > >
> > > 2. It doesn't, and whatever happens happens, depending on what the
> > > C library does on a give platform, or:
> > >
> > > 3. It issues an error or warning message, and possibly takes either
> > > of the above actions as well.
> > >
> > > I just experimented with a test script using "%lf" and perl didn't
> > > complain, even with the -w option.  So the third possibility above
> > > appears not to be happening.
> > >
> > > In any case, it seems like there's no good reason to use "%lf" in
> > > Perl, any more than in C.
> > >
> > > Disclaimer: my knowledge of Perl doesn't extend much beyond how to
> > > spell it.
> > >
> > > Scott McKellar
> > > http://home.swbell.net/mck9/aargh/
> > >
> > >
> > > --- Joe Atzberger <atzberger at MECDC.ORG> wrote:
> > >
> > >> Perl accepts "%lf" as an accepted format for printf and sprintf.  It
> > >> would only be particularly meaningful on a system
> > >> where the default size of a floating point number was not long double
> > >> (i.e., double or quad).
> > >>
> > >>  From perldoc:
> > >>      http://perldoc.perl.org/functions/sprintf.html
> > >>    "For floating point conversions (e f g E F G), numbers are usually
> > >> assumed to be the default floating point size on
> > >> your platform (double or long double), but you can force 'long
> > >> double' with q, L , or ll if your platform supports them."
> > >>
> > >> Interestingly, this may conflict with the fact that perl's sprintf
> > >> actually invokes the C version for floating point
> > >> numbers:
> > >>    "Perl does its own sprintf formatting--it emulates the C function
> > >> sprintf, but it doesn't use it (*except for
> > >> floating-point numbers*, and even then only the standard modifiers
> > >> are allowed)."
> > >>
> > >> So based on that, I'm more confused than anything.  It seems like it
> > >> should only be a question of what the C version
> > >> supports for floats, even if perl doesn't report a warning/error.
> > >>
> > >> --Joe Atzberger
> > >> INFOhio Technical Specialist
> > >> Metropolitan Educational Council
> > >> (614) 473-8300 x22
> > >> atzberger at mecdc.org
> > >
> > > <snip>
> >
> >
>
>
> --
> Mike Rylander
>


-- 
Mike Rylander