[Bug libstdc++/44663] New: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[Bug libstdc++/44663] New: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[pluto at agmk dot net]

hi,

the latest llvm/clang++ reports an error during parsing <tr1/tuple>
included from <tr1/functional>:

In file included from t00.cpp:1:
In file included from /usr/include/c++/4.5.0/tr1/functional:39:
/usr/include/c++/4.5.0/tr1/tuple:68:30: error: variadic templates are only
allowed in C++0x
  template<int _Idx, typename... _Elements>

afaics there's no #ifdef __GXX_EXPERIMENTAL... guards but...

http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#manual.intro.status.standard.200x

(...)
In this implementation -std=gnu++0x or -std=c++0x flags must be used
to enable language and library features. The pre-defined symbol
__GXX_EXPERIMENTAL_CXX0X__ is used to check for the presence of
the required flag.
(...)


-- 
           Summary: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?
           Product: gcc
           Version: 4.5.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pluto at agmk dot net
  GCC host triplet: x86_64-gnu-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663

[Bug libstdc++/44663] missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[redi at gcc dot gnu dot org]

------- Comment #1 from redi at gcc dot gnu dot org  2010-06-25 11:08 -------
(In reply to comment #0)
> the latest llvm/clang++ reports an error during parsing <tr1/tuple>
> included from <tr1/functional>:
> 
> In file included from t00.cpp:1:
> In file included from /usr/include/c++/4.5.0/tr1/functional:39:
> /usr/include/c++/4.5.0/tr1/tuple:68:30: error: variadic templates are only
> allowed in C++0x

That's Clang's problem, not GCC's :-)

They are supported as an extension in g++, so we can use them to implement
components like tr1::tuple.  (I think the original implementation of variadic
templates was done by Douglas Gregor, who's now working on Clang.)

See also Bug 43824


-- 

redi at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663

[Bug libstdc++/44663] missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[redi at gcc dot gnu dot org]

------- Comment #2 from redi at gcc dot gnu dot org  2010-06-25 11:55 -------
http://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.other_compilers

If the guards were there as you suggest, tr1::tuple would only be usable in
C++0x mode, where it's redundant because you have std::tuple anyway.

g++ is the only compiler officially supported by libstdc++, so personally I'm
opposed to disabling functionality to support other compilers.  I'm not opposed
to changes that don't affect functionality for g++ users e.g. if non-standard
features are used unnecessarily and could be replaced with equivalent standard
features.  That doesn't apply here, as the advantages of variadic templates are
huge.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663

[Bug libstdc++/44663] missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[paolo dot carlini at oracle dot com]

------- Comment #3 from paolo dot carlini at oracle dot com  2010-06-25 11:59 -------
Totally agree.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663

[Bug libstdc++/44663] missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[pinskia at gmail dot com]

------- Comment #4 from pinskia at gmail dot com  2010-06-25 14:18 -------
Subject: Re:   New: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?



On Jun 25, 2010, at 3:49 AM, "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

> hi,
>
> the latest llvm/clang++ reports an error during parsing <tr1/tuple>
> included from <tr1/functional>:

Both of these are c++0x only headers and really are only supported  
when compiling in c++0x mode.


>
> In file included from t00.cpp:1:
> In file included from /usr/include/c++/4.5.0/tr1/functional:39:
> /usr/include/c++/4.5.0/tr1/tuple:68:30: error: variadic templates  
> are only
> allowed in C++0x
>  template<int _Idx, typename... _Elements>
>
> afaics there's no #ifdef __GXX_EXPERIMENTAL... guards but...
>
> http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#manual.intro.status.standard.200x
>
> (...)
> In this implementation -std=gnu++0x or -std=c++0x flags must be used
> to enable language and library features. The pre-defined symbol
> __GXX_EXPERIMENTAL_CXX0X__ is used to check for the presence of
> the required flag.
> (...)
>
>
> -- 
>           Summary: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?
>           Product: gcc
>           Version: 4.5.1
>            Status: UNCONFIRMED
>          Severity: normal
>          Priority: P3
>         Component: libstdc++
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: pluto at agmk dot net
>  GCC host triplet: x86_64-gnu-linux
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663

Re: [Bug libstdc++/44663] New: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[Andrew Pinski]

On Jun 25, 2010, at 3:49 AM, "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

> hi,
>
> the latest llvm/clang++ reports an error during parsing <tr1/tuple>
> included from <tr1/functional>:

Both of these are c++0x only headers and really are only supported  
when compiling in c++0x mode.


>
> In file included from t00.cpp:1:
> In file included from /usr/include/c++/4.5.0/tr1/functional:39:
> /usr/include/c++/4.5.0/tr1/tuple:68:30: error: variadic templates  
> are only
> allowed in C++0x
>  template<int _Idx, typename... _Elements>
>
> afaics there's no #ifdef __GXX_EXPERIMENTAL... guards but...
>
> http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt01ch01.html#manual.intro.status.standard.200x
>
> (...)
> In this implementation -std=gnu++0x or -std=c++0x flags must be used
> to enable language and library features. The pre-defined symbol
> __GXX_EXPERIMENTAL_CXX0X__ is used to check for the presence of
> the required flag.
> (...)
>
>
> -- 
>           Summary: missed GXX_EXPERIMENTAL guards in <tr1/tuple>?
>           Product: gcc
>           Version: 4.5.1
>            Status: UNCONFIRMED
>          Severity: normal
>          Priority: P3
>         Component: libstdc++
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: pluto at agmk dot net
>  GCC host triplet: x86_64-gnu-linux
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663
>

[Bug libstdc++/44663] missed GXX_EXPERIMENTAL guards in <tr1/tuple>?

[paolo dot carlini at oracle dot com]

------- Comment #5 from paolo dot carlini at oracle dot com  2010-06-25 14:23 -------
Wrong Andrew.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44663