Compilation of <vector> and self-defined 'distance(a,b)' fails

Compilation of <vector> and self-defined 'distance(a,b)' fails

[Benjamin King]

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Hi GCC team,

I think my gcc has a bug. It fails to compile the following program. Renaming 'distance' to anything else solves this, so I guess that the 'distance' function from <iterator> somehow escaped the std::-namespace.
I couldn't find any description about this with google or in the gcc bug database.

cheers,
   Benjamin


My code (see attachment for .ii):
---
#include <vector>

double distance(const std::vector<double> & v1, const std::vector<double> & v2) {
   return 0;
}

int main(int argc, char* argv[])
{
   std::vector<double> v;
   double d;
   d = distance(v, v);
   return 0;
}
---


gcc -v:
---
Reading specs from /usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/specs
Configured with: /var/tmp/portage/gcc-3.3.2-r5/work/gcc-3.3.2/configure --prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/3.3 --includedir=/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/include --datadir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3 --mandir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3/man --infodir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3/info --enable-shared --host=i686-pc-linux-gnu --target=i686-pc-linux-gnu --with-system-zlib --enable-languages=c,c++,f77,objc,java --enable-threads=posix --enable-long-long --disable-checking --enable-cstdio=stdio --enable-clocale=generic --enable-__cxa_atexit --enable-version-specific-runtime-libs --with-gxx-include-dir=/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/include/g++-v3 --with-local-prefix=/usr/local --enable-shared --enable-nls --without-included-gettext --x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib --enable-interpreter --enable-java-awt=xlib --with-x --disable-multilib
Thread model: posix
gcc version 3.3.2 20031218 (Gentoo Linux 3.3.2-r5, propolice-3.3-7)
---


Command line:
---
gcc -pedantic -Wall minifail.cpp
---


Compiler output:
---
/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/include/g++-v3/bits/stl_iterator_base_types.h: In instantiation of `std::iterator_traits<std::vector<double, std::allocator<double> > >':
minifail.cpp:11:   instantiated from here
/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/include/g++-v3/bits/stl_iterator_base_types.h:126: error: no
    type named `iterator_category' in `class std::vector<double,
    std::allocator<double> >'
---

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Re: Compilation of <vector> and self-defined 'distance(a,b)' fails

[Jim Wilson]

Benjamin King wrote:
> I think my gcc has a bug. It fails to compile the following program. 
> Renaming 'distance' to anything else solves this, so I guess that the 
> 'distance' function from <iterator> somehow escaped the std::-namespace.

Filing bug reports into our bugzilla bug tracking database is better 
than sending mail to gcc-bugs, as we don't track bug reports mailed to 
the list.  The result is that you are more likely to get a useful 
response if you use bugzilla.  See
     http://gcc.gnu.org/bugs.html
for more info on reporting bugs.

I am not a C++ expert, so I am really not the right person to be looking 
at this.  However, I suspect the problem is that the vector class is 
itself defined in namespace std, and uses the iterator classes, and that 
is somehow causing the search for the distance function to also look at 
the interator classes.  It isn't just the name distance, any name in 
stl_interator.h seems to cause the same problem.

I can get your testcase to compile if I change
   d = distance(v, v);
to
   d = ::distance(v, v);
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com