i have a problem with SIGUSR1 and SIGUSR2 i coudnt understand it.... could you help me with this problem: Write a C program (give it the name: family.c) which receives no arguments. The program should fork exactly two children. One child should sleep for 2 seconds and then send the signal SIGUSR1 to his parent. The other child should sleep for 5 seconds and then send the signal SIGUSR2 to his parent. The parent, while busy counting from 0 to 9 –sleeping one second after each count- will ignore the first signal but handle the other signal with a signal handler that just prints the following: “Son! Stop making noise!” this my solution but without using the signal int main (void) { int child_pid; int child_pid1; int i; /* define the signal handler for the CHLD signal */ /* and the child process forking code... */ child_pid = fork(); switch (child_pid) { case -1: /* fork() failed */ perror("fork"); exit(1); case 0: /* inside child process */ sleep(2); /* sleep a little, so we'll have */ /* time to see what is going on */ exit(0); default: /* inside parent process */ break; child_pid1 = fork(); switch (child_pid1) { case -1: /* fork() failed */ perror("fork"); exit(1); case 0: /* inside child process */ sleep(5); /* sleep a little, so we'll have */ /* time to see what is going on */ exit(0); default: /* inside parent process */ break; } /* parent process goes on, minding its own business... */ /* for example, some output... */ for (i=0; i<10; i++) { printf("%d\n", i); sleep(1); /* sleep for a second, so we'll have time to see the mix */ } return 0; }

... default: /* inside parent process */ break; <=== The problem is here. Remove this line. child_pid1 = fork(); switch (child_pid1) { case -1: /* fork() failed */ perror("fork"); exit(1); case 0: /* inside child process */ ... Luke Chi