I'm trying to get the threads library to link. I've built all the libraries using bjam (--toolset=darwin) and they are in /usr/local/lib (e.g., libboost_thread-mt-1_35.dylib). However, when I execute this (from make, but this is the crux): g++ -funsigned-char -I ~/Desktop/Work/boost_1_35_0/ main.cpp -L /usr/local/lib -lboost_thread-mt-1_35 -t -pthread -o lock_free it fails with this output: In file included from /usr/include/c++/4.0.0/backward/strstream:51, from enforce.h:10, from main.cpp:5: /usr/include/c++/4.0.0/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the header for C++ includes, or <iostream> instead of the deprecated header . To disable this warning use -Wno-deprecated. *ld: in /usr/local/lib, can't map file, errno=22 /usr/lib/crt1.10.5.o collect2: ld returned 1 exit status* make: *** [lock_free] Error 1 Any ideas? At first I thought it was a boost library error, but then I added the -t linker option and the /usr/lib/crt1.10.5.o showed up. Thanks in advance -