Re: [avr-libc-dev] [bug #28837] using PSTR with c++ produces warnings

[Weddington, Eric]

Hi All,

FYI, David Mellis (who wrote the message below) is a member of the core
Arduino team. You can see him in a picture with this article:

http://spectrum.ieee.org/geek-life/hands-on/the-making-of-arduino

These are a group of really good guys. They like the AVR, and they like
the AVR GCC toolchain, because of how quickly and easily it enabled them
to do their project.

One of the eye-opening things for me about the Arduino project is the
fact that they generate C++ code for the AVR. Before, I had been on the
fence about using C++ on the AVR. I thought that it might have been a
bit on the overkill side. Perhaps I've been prejudiced because I grew up
using C, a lot. But regardless of what any engineering professional here
may think about the Arduino language itself, or the inexperience of
their user base, I think that the Arduino project has proven is that C++
can be used on the AVR in real-world projects. I find this to be pretty
exciting.

It means, to me, that we (as developers working on the AVR toolchain)
need to look at more than just the C compiler. That we need to continue
to advance in the C++ compiler capabilities, e.g., Joerg and I have
talked for years about trying to get libstdc++ built for the AVR. With
on-again, off-again work on it. Now there is more of an incentive to
continue with that.

@David: The first step in working together to solve problems in the
toolchain is the bug report. It's ok if you haven't investigated deeply
as to the cause of the failure. But we need to know about the bugs to
help you guys out. Submitting bug reports to either the binutils or GCC
bug databases, that have reproducible bugs, with test code is what is
really needed. And if you need any help with that then let us know, and
we can walk you through the ropes.

Eric Weddington


> -----Original Message-----
> From: David A. Mellis 
> Sent: Monday, October 31, 2011 7:15 AM
> To: Weddington, Eric
> Cc: Joerg Wunsch; address@hidden
> Subject: Re: [avr-libc-dev] [bug #28837] using PSTR with c++ produces
> warnings
> 
> Thanks for the message, Eric.
> 
> As you say, we don't really have enough time to properly investigate
the
> toolchain and bugs.  I've had various reports of various Arduino
functions
> breaking with newer versions of binutils (2.21, I believe) and haven't
had
> the resources to track those reports down to the underlying toolchain
bugs
> or changes.
> 
> Of course, I have lots of respect and appreciation for all the work
you
> guys do.  And I realize that vague reports of problems don't help you
fix
> them.  That's why in general I've just gone with whatever Eric
packages up
> in WinAVR as the toolchain for Arduino.  We're eagerly awaiting the
next
> release.  :)
> 
> David
> 
> On Oct 31, 2011, at 9:02 AM, Weddington, Eric wrote:
> 
> >
> >
> >> -----Original Message-----
> >> From: address@hidden
> >> [mailto:address@hidden
On
> >> Behalf Of Joerg Wunsch
> >> Sent: Saturday, October 29, 2011 4:25 PM
> >> To: address@hidden
> >> Subject: Re: [avr-libc-dev] [bug #28837] using PSTR with c++
produces
> >> warnings
> >>
> >> As Volker Kuhlmann wrote:
> >>
> >>>> Just because someone at Arduino thinks ``4.4.x and 4.5.x seem to
> > have
> >>>> various problems'' is enough to make you not using them?
> >>>
> >>> Yes, definitely. Why?
> >>>
> >>> I have no other information and know nothing about the avr-gcc
> > specific
> >>> issues in gcc.
> >>
> >> The least you could expect them is to explicitly mention *which*
> >> problems they have found, either (and preferrably) as references to
> >> GCC bug reports, or at least, as detailed descriptions about the
> >> problems someone encountered.
> >>
> >> Without that, it's just babbling.  FUD.  (Fear, uncertainty, and
> >> doubt.)  I could tell you as well about GCC 4.3.x having ``several
> >> problems'', and by digging through the GCC bug database, I could
> >> probably even found this sentences with some substance. ;-)
> >>
> >
> > Volker, Joerg,
> >
> > To be fair, the Arduino project is like any other open source
project in
> > that they are chronically short of help and they can only focus on
there
> > area of expertise.
> >
> > I've talked quite a bit with one of the co-founders of the project,
met
> > the whole team, and various other people who help here and there on
the
> > Arduino project.
> >
> > The Arduino project focuses on a number of things:
> > - Their hardware design
> > - Their IDE / language
> > - Their support libraries
> >
> > What they don't do is the toolchain themselves. Two reasons why
Arduino
> > was able to easily get off the ground is the fact that the AVR
> > microcontroller itself is easy to use, and the fact that there is a
> > free/open source toolchain (GCC) for the AVR. It also helped that
WinAVR
> > existed as they just dropped the WinAVR toolchain in their installer
> > package for the Windows platform.
> >
> > So please realize that they are not *trying* to spread FUD. They
just
> > don't have the resources to tackle the toolchain issues in-depth.
> >
> > The last thing to remember is that they (Arduino) exercise different
> > areas of the toolchain then most other people. Most users of the AVR
GCC
> > toolchain use the C compiler. The Arduino community is the first
large
> > set of users that use the C++ compiler for the AVR, which
admittedly,
> > hasn't gotten much attention previously.
> >
> > HTH,
> > Eric Weddington
> >
> > _______________________________________________
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> > address@hidden
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