Hi, When using precompiled headers, BOOST_TYPEOF_REGISTER_TYPE() macro throw some erros. stdafx.h: --- #pragma once #ifndef _WIN32_WINNT // Allow use of features specific to Windows XP or later. #define _WIN32_WINNT 0x0501 // Change this to the appropriate value to target other versions of Windows. #endif #include --- test_boost_auto.cpp : --- #include "stdafx.h" // 1 //#include // 2 #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() class A { }; BOOST_TYPEOF_REGISTER_TYPE(A) int main() { return 0; } --- When "USE precompiled headers" is turned on, the above code return this error when compiled: --- ------ Build started: Project: test_boost_auto, Configuration: Debug Win32 ------ Compiling... test_boost_auto.cpp d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2143: syntax error : missing ';' before '<' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2059: syntax error : '<' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2653: 'a' : is not a class or namespace name d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2065: 'V' : undeclared identifier d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2143: syntax error : missing ';' before '{' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2447: '{' : missing function header (old-style formal list?) d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2143: syntax error : missing ';' before '<' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2059: syntax error : '<' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2143: syntax error : missing ';' before '{' d:\temp\delete\test_boost_auto\test_boost_auto.cpp(9) : error C2447: '{' : missing function header (old-style formal list?) Build log was saved at "file://d:\Temp\DELETE\test_boost_auto\Debug\BuildLog.htm" test_boost_auto - 10 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== --- When I turn off precompiled headers, comment #include "stdafx.h" and uncomment //#include // 2 everythings compile fine. thanks Trigve ____________________________________________________________________________________Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545469