Re: [Boost-users] [Spirit] puts namespace std into the global scope

3 Jul 2006


      Johan Råde wrote:
...
It seems that the header boost/spirit.hpp puts
the entire namespace std into the global scope.
That is not very nice!
--- Example 1 --------
#include <string>
#include <sstream>
#include <fstream>
#include <vector>
#include <boost/spirit.hpp>
void f()
{
     string s;
     istringstream iss;
     ofstream ofs;
     vector<int> v;
}
----------------------
Example 1 should not compile (undefined symbols), but does compile.
If the line #include <boost/spirit.hpp> is removed,
then Example 1 does not compile.
--- Example 2 --------
#include <boost/filesystem/path.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/spirit.hpp>
using boost::filesystem::path;
using boost::filesystem::ifstream;
void g()
{
     path p;
     ifstream ifs(p);
}
----------------------
Example 2 should compile but does not.
The compiler complains that the symbol ifstream is ambigous.
If the line #include <boost/spirit.hpp> is removed,
then Example 2 does compile.
I´m using Boost 1.33.1 and MSVC 7.1 on a Windows XP computer.
IIRC, that comes from VC++ fatal bug about "using directive",
and was already fixed under RC_1_34.


-- 
Shunsuke Sogame