This signal is raised a user defined number of seconds after the alarm(2) syscall is called. The default action of this signal is to terminate the program. This signal is often used for timeouts on syscalls. Be aware that other processes can send you a SIGALRM before your timeout is up if they are owned by the same user or root, so using this to enforce a timeout doesn't work, investigate using select(2) in that instance.
3 pages link to SIGALRM:
