I am trying to use boost 1.47 on cygwin 1.7 cross-compiling to win32 with i686-w64-mingw32-g++ (4.5.3). This program gives me an error: #include <boost/thread/tss.hpp> int main() { boost::thread_specific_ptr<int> ts; return 0; } $ i686-w64-mingw32-g++ -o mgw-release/obj/Tests/toto.o -c -O3 -DNDEBUG -Wall -Wextra -pipe -mthreads -I/cygdrive/d/Softs/1.7/mgw-release/boost/include -I. Tests/toto.cc In file included from /cygdrive/d/Softs/1.7/mgw-release/boost/include/boost/thread/detail/thread_heap_alloc.hpp:15:0, from /cygdrive/d/Softs/1.7/mgw-release/boost/include/boost/thread/tss.hpp:10, from Tests/toto.cc:1: /cygdrive/d/Softs/1.7/mgw-release/boost/include/boost/thread/win32/thread_heap_alloc.hpp:59:40: warning: inline function ‘void* boost::detail::allocate_raw_heap_memory(unsigned int)’ declared as dllimport: attribute ignored /cygdrive/d/Softs/1.7/mgw-release/boost/include/boost/thread/win32/thread_heap_alloc.hpp:69:39: warning: inline function ‘void boost::detail::free_raw_heap_memory(void*)’ declared as dllimport: attribute ignored $ i686-w64-mingw32-g++ -o mgw-release/bin/toto -O3 -DNDEBUG -Wall -Wextra -pipe -mthreads -I/cygdrive/d/Softs/1.7/mgw-release/boost/include mgw-release/obj/Tests/toto.o -Wl,--enable-auto-import -static -L/cygdrive/d/Softs/1.7/mgw-release/boost/lib -lboost_thread_win32 mgw-release/obj/Tests/toto.o:toto.cc:(.text+0x104): undefined reference to `__imp___ZN5boost6detail12set_tss_dataEPKvNS_10shared_ptrINS0_20tss_cleanup_functionEEEPvb' collect2: ld returned 1 exit status any help would be welcome. Regards, Frédéric