I've noticed that in boost/config/platform/hpux.hpp this lines: #ifdef __GNUC__ // GNU C on HP-UX does not support threads (checked up to gcc 3.3) # define BOOST_DISABLE_THREADS #endif have been added in version 1.30.x. Please, ¿can someone explain me why? I have commented out the #define BOOST_DISABLE_THREADS and it works in gcc 3.2 with HP-UX 11.00. We do not use Jam to build the library, but I think that that doesn't matter. gcc --version: gcc (GCC) 3.2 Copyright (C) 2002 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. uname -a: HP-UX habana B.11.00 A 9000/778 2004658305 two-user license Thanks in advance, -- Raúl Huertas Díaz