Re: [Boost-users] Context and coroutine for ARM

Subject: Re: [Boost-users] Context and coroutine for ARM
From: Daniel Estermann (estermad_at_[hidden])
Date: 2017-05-13 18:51:19

I have to add that it seems to have nothing to do with my cross compiler
though. I must have bumped into a known gcc bug, which was fixed only in
version 7.0.0: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58938

Marked as duplicate std::future must be affected as well:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64735

I am a bit surprised the code compiled on Pi, but I think they fixed that
somehow in their own branch of gcc (since its version is 4.9.2*-10*)

pi_at_rpi1 ~ $ g++ -v
...
gcc version 4.9.2 (Raspbian 4.9.2-10)

2017-05-13 20:15 GMT+02:00 Daniel Estermann <estermad_at_[hidden]>:

> Thank you again for your responses.
>
> First of all to clarify the my different logs with gnueabihf and gnueabi.
> The one of them runs in my native environment, i.e. in Cygwin, the other
> one in a Virtual Box on a Linux. To make sure that the errors are not
> Cygwin related. So these installations aren't mixed.
>
> >First, why in the world do you want to declare an exception variable apart
> from a try/catch block?
> I think this it sufficient to see if that type is declared at all.
>
> From compiling the example with '-v' I learned the location of the
> included exception header. At the end of this header I saw:
>
> #if (__cplusplus >= 201103L) && (ATOMIC_INT_LOCK_FREE > 1)
> #include <bits/exception_ptr.h>
> #include <bits/nested_exception.h>
> #endif
>
> Playing around with #error's I found out ATOMIC_INT_LOCK_FREE is set to 1
> so this condition isn't fulfilled. The next thing i tried out is to comment
> that condition. The result was:
>
> /cygdrive/d/Development/x-tools/arm-unknown-linux-
> gnueabihf/arm-unknown-linux-gnueabihf/include/c++/6.3.0/bits/nested_exception.h:43:4:
> error: #error This platform does not support exception propagation.
>
> I checked then if this example compiles on Pi. It worked. So it seems I
> have to rebuild my cross-compiler. Do you maybe know which option should I
> pay attention to, to have this option set?
>
>
> 2017-05-13 18:41 GMT+02:00 d25fe0be_at_[hidden] <d25fe0be_at_[hidden]>:
>
>> Try compiling it with '-v' (g++ -v t.cpp) so that the include search
>> paths are printed ('#include <...> search starts here: ...'), and examine
>> them to see if there is some other implementation (which presumably does
>> not implement std::exception_ptr) of STL is included and takes precedence
>> over the libstdc++ coming with GCC 6.3.
>>
>> If there is, I suggest you do a clean build of your cross-compiling
>> toolchain.
>>
>> I also noticed that this time you're using `arm-unknown-linux-gnueabihf-gcc`
>> (an unknown version) instead of `arm-unknown-linux-gnueabi-gcc` (which
>> should be 6.3.0 from your previous post), and they seems to be two
>> different installations. I'm not sure if this is related, but there's a
>> chance that the two installations are messed together in some way, which
>> may cause some problems.
>>
>> > On 14 May 2017, at 00:11, Daniel Estermann via Boost-users <
>> boost-users_at_[hidden]> wrote:
>> >
>> > Thanks for the minimal example hint. Here is what I get:
>> >
>> > $ arm-unknown-linux-gnueabihf-gcc -xc++ - <<EOF
>> > > #include <exception>
>> > >
>> > > std::exception_ptr x;
>> > >
>> > > int main() {}
>> > >
>> > > EOF
>> > <stdin>:3:6: error: 'exception_ptr' in namespace 'std' does not name a
>> type
>> >
>> >
>> > 2017-05-13 17:05 GMT+02:00 d25fe0be_at_[hidden] <d25fe0be_at_[hidden]>:
>> > It may be worth to try to compile the following code snippet to see if
>> your compiler is working as expected:
>> >
>> > $ cat t.cpp
>> > #include <exception>
>> >
>> > std::exception_ptr x;
>> >
>> > int main() {}
>> > $ g++-6 ./t.cpp
>> > $
>> >
>> > Perhaps your compiler (or libstdc++) is broken in some way.
>> >
>> > > On 13 May 2017, at 21:17, Daniel Estermann via Boost-users <
>> boost-users_at_[hidden]> wrote:
>> > >
>> > > No matter if I add -std=c++11 to the flags, I still get the error
>> message: http://sprunge.us/gSXb
>> > > This is my compiler's configuration: http://sprunge.us/iaWZ
>> > > I'm not sure how to check why C++11 code is used though.
>> > >
>> > >
>> > >
>> > > 2017-05-13 15:02 GMT+02:00 Oliver Kowalke via Boost-users <
>> boost-users_at_[hidden]>:
>> > > exception_ptr is part of C++11 but not used in boost.coroutine (and
>> the fcontext-API of boost.context) -
>> > > you could apply -std=c++11(cxxflags) or check why C++11 code is used
>> > >
>> > > _______________________________________________
>> > > Boost-users mailing list
>> > > Boost-users_at_[hidden]
>> > > https://lists.boost.org/mailman/listinfo.cgi/boost-users
>> > >
>> > > _______________________________________________
>> > > Boost-users mailing list
>> > > Boost-users_at_[hidden]
>> > > https://lists.boost.org/mailman/listinfo.cgi/boost-users
>> >
>> >
>> >
>> > _______________________________________________
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>>
>>
>