If you are using TotalView for the first time or you have just started using NPTL instead of Linuxthreads you may notice that your application is behaving differently under TotalView. In many cases this may be due to a call to sem_wait() or sigwait() failing. With Linuxthreads, sem_wait and sigwait were specified not to fail. However this has changed with NPTL. Both functions may now return -1 and store EINTR in errno. If 'man sem_wait' or 'man sigwait' do not tell you this see 'man 3p sem_wait' or 'man 3p sigwait' for the correct information. If your application is not checking for error after calls to sem_wait or sigwait than this is the likely cause for the different behavior when run under TotalView. Please see the [url http://forum.etnus.com/gforum.cgi?post=43#43]FAQ on SIGSTOP[/url] for further information.