This signal is used for statistical profiling. The default action is to terminate the process
See http://charm.cs.uiuc.edu/users/olawlor/ref/examples/unix/setitimer_pc.c for an example of using this for profiling.
2 pages link to SIGPROF:
http://charm.cs.uiuc.edu/users/olawlor/ref/examples/unix/setitimer_pc.c for an example of using this for profiling.