[boost] Global vars

From: Paul Hamilton (paul_at_[hidden])
Date: 2003-08-18 12:04:33

Well,

I've tried to work through the solutions to:

ld: common symbols not allowed with MH_DYLIB output format

Which are basically "-fno-common" on the compile line of each file, but 
apart from the fact that tihs doesn't actually work in this case (we 
still get the error), it's not really a very good idea.

Does anybody have any suggestions for working around this code:

namespace boost {
namespace io {
namespace detail {
namespace  {

   template<class Tr, class Ch> inline
   void empty_buf(BOOST_IO_STD basic_ostringstream<Ch,Tr> & os) {
     static const std::basic_string<Ch, Tr> emptyStr;
     os.str(emptyStr);
   }

};};};};

The correct thing to do with this code (for all platforms) is to not 
rely on the global variable "common" stuff (which is new to me, and 
seems a bit of a hack), but actually do this code correctly, which 
means removing the global variable.

What problem is the code above trying to solve?

If i just do this (which i have done to get my stuff working), there 
seems to be no prob:

#ifdef MACHACK
   template<class Tr, class Ch> inline
   void empty_buf(BOOST_IO_STD basic_ostringstream<Ch,Tr> & os) {
     extern const std::basic_string<Ch, Tr> emptyStr;
     os.str(emptyStr);
   }
#else
        #define empty_buf(_os_)		(_os_).str("");
#endif

Wouldn't the above two lines achieve basically the same thing (although 
I know we hate macros, but since "empty_buf" is only actually used 3 
times in the entire project, could all of the:

        empty_buf(oss);

be replaced with:

        oss.str("");

This would save a whole lot of grief and eliminate this fairly ugly 
global variable.

Comments?

---------------------
Paul Hamilton
pHamtec P/L - Software Makers
http://www.phamtec.com/
mailto:paul_at_[hidden]

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