Hi dear all, What is the boost STL including logic ? I'm using WDK build enveriment which include a STL70 of MS . Following is the detail message 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\warning.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\suppress.h 1>Note: including file: D:\boostlib\boost\tr1\tr1\iostream 1>Note: including file: D:\boostlib\boost/tr1/detail/config_all.hpp 1>Note: including file: D:\WinDDK\7600.16385.0\inc\crt\cstddef 1>Note: including file: D:\WinDDK\7600.16385.0\inc\crt\stddef.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\crt\crtdefs.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\specstrings.h 1>Note: including file: d:\winddk\7600.16385.0\inc\api\sal_supp.h 1>Note: including file: d:\winddk\7600.16385.0\inc\api\specstrings_supp.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\sal.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\specstrings_strict.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\specstrings_undef.h 1>Note: including file: D:\WinDDK\7600.16385.0\inc\api\driverspecs.h 1>Note: including file: d:\winddk\7600.16385.0\inc\api\sdv_driverspecs.h 1>d:\boostlib\boost\tr1\detail\config_all.hpp(48) : fatal error C1083: Cannot open include file: 'cstdlib': No such file or directory Thanks in advance