Hello all, Into Boost, this macro is defined between a !defined # if !defined(__CYGWIN__) && !defined(__QNXNTO__) # define BOOST_TEST_USE_ALT_STACK # endif Should we add a C++ macro provided by the compiled to disable this define ? That seems to be the right thing to do since sigaltstack doesn't appear to be valid on your platform. I recompiled boost.test using gcc of the compute node (not xlc). I use gcc because the performances of xlc with meta-programming are bad (the inlining does not work). For my work, I utilise an experimental clang + boost compiled with gcc. So into 1.54/include/boost/test/impl/execution_monitor.ipp, I did 176 # if !defined(__CYGWIN__) && !defined(__QNXNTO__) &&! defined(__bgq__) 177 # define BOOST_TEST_USE_ALT_STACK 178 # endif I recompiled the library, and my tests using static link or the include version of the lib (I use a large sets of feature of the framework) I have a correct execution of my tests with the patch. Can you verify that this function is not supported on Bluegene/Q? If it is not supported, then it seems that the right change is to add a check for __bgq__ or __bg__ and not define BOOST_TEST_USE_ALT_STACK if the appropriate symbol is defined. We test a small test case (thank Sam): "BG/Q compute nodes do not support the establishment of an alternate signal stack using sigaltstack() and sigaction(). The example code when compiled with bgxlc & gcc (compute node) and run on a compute node produces an error output." #include <signal.h> #include <stdio.h> #include <errno.h> void handler(int sig) {} int main() { static char stack_buf[SIGSTKSZ]; stack_t stack={ .ss_sp=stack_buf, .ss_flags=0, .ss_size=SIGSTKSZ}; int rv; rv=sigaltstack(&stack,0); if (rv) perror("sigaltstack"); struct sigaction sa={ .sa_handler=handler, .sa_flags=SA_ONSTACK}; sigfillset(&sa.sa_mask); rv=sigaction(SIGSEGV,&sa,0); if (rv) perror("sigaction"); return 0; } We get : % bgxlc sigaction_altstack.c % srun -n1 ./a.out sigaltstack: Function not implemented sigaction: Invalid argument % This behaviour about sigaction is considered as a bug ? Should open a ticket somewhere ? Will it be patched for the next release of boost ? Cheers, Tim