i had tried to compile circular buffer sample with mingw gcc-4.5.0-1
http://sourceforge.net/projects/mingw/files/

1. a.exe(circular buffer in boost-1.42) got runtime error
2. llvm-2.7 got runtime error

so i have built mingw gcc-4.4.4 with mingw gcc-4.5.0-1
Now, mingw gcc 4.4.4 works fine with circular buffer.

:)