sigalrm
signal(SIGALRM, sigalrm);
sa.sa_handler = &sigalrm;
void sigalrm(int);
sa.sa_handler = sigalrm;
sa.sa_handler = sigalrm;
SIGTYPE sigalrm(int signo);
signal(SIGALRM, sigalrm); /* that can cause hanging in read() */
signal(SIGALRM, sigalrm);