gcc-3.3 issues

[Jacques A. Vidrine]

[cc: list trimmed]

On Fri, Jul 18, 2003 at 10:32:51AM +0200, Michael Nottebrock wrote:
> I've tried to come up with a less obscure testcase:
> 
> #include <string>
> #include <iostream>
> using namespace std;
> 
> int main ()
> {
> 
>   string astring="Hello World";
>   cout << astring << endl;
> }
> 
> Now, if I compile this on 5.1-RELEASE with 
> 
> c++ -Wnon-virtual-dtor -Wno-long-long -Wall -pedantic -W -Wpointer-arith 
> -Wmissing-prototypes -Wwrite-strings -DNDEBUG -DNO_DEBUG -O -pipe 
> -mcpu=pentiumpro -fno-check-new -L/usr/local/lib -I/usr/local/include 
> -I/usr/local/include -I/usr/X11R6/include -D_GETOPT_H -o helloworld 
> helloworld.cc
> 
> I get a plethora of warnings:
> 
> In file included from /usr/include/g++/memory:55,
>                  from /usr/include/g++/string:48,
>                  from helloworld.cc:1:
> /usr/include/g++/bits/stl_alloc.h:979: warning: ISO C++ forbids the use of `
>    extern' on explicit instantiations
> /usr/include/g++/bits/stl_alloc.h:980: warning: ISO C++ forbids the use of `
>    extern' on explicit instantiations
> /usr/include/g++/bits/stl_alloc.h:981: warning: ISO C++ forbids the use of `
>    extern' on explicit instantiations
> /usr/include/g++/bits/stl_alloc.h:981: warning: ISO C++ forbids the use of `
>    extern' on explicit instantiations
> /usr/include/g++/bits/stl_alloc.h:981: warning: ISO C++ forbids the use of `
>    extern' on explicit instantiations
> 
> [and many, many more]
> 
> but it will compile. If I omit -pedantic, none of these warnings occur. The 
> thing is, in -CURRENT with the new gcc, all these warnings for some reason 
> become errors. The other thing is, if I try this with with a ports-compiled 
> g++32 on 4-STABLE, I don't get warnings at all, no matter if -pedantic is 
> specified or not.
> 
> So here's the questions for the experts:
> 
> - Why errors instead of warnings?
> - Why do gcc's own bits seem to not conform to some kind of standard that it 
> tries to adhere to in 5-CURRENT but not in 4-STABLE?
> - Who's to blame?

I haven't looked recently, but I seem to recall that the STL and other
C++ header bits that we install in /usr/include are from an older GCC
release than the compiler.  On my pre-GCC 3.3 -CURRENT system:

 System compiler:
   % g++ -c -Wall -pedantic hello.cc
   <many warnings>

 GCC 3.2 from ports:
   % g++32 -c -Wall -pedantic hello.cc
   <no warnings>

 GCC 3.3 from ports:
   % g++33 -c -Wall -pedantic hello.cc
   <no warnings>

I also recall lots of missing `typename's in the system headers that were
resolved in the actual GCC distribution.

Alexander, do the STL headers et. al. get updated with the rest of the
compiler chain?

Cheers,
-- 
Jacques Vidrine   . NTT/Verio SME      . FreeBSD UNIX       . Heimdal
nectar at celabo.org . jvidrine at verio.net . nectar at freebsd.org . nectar at kth.se