add FITS.

sigtest.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+#include <signal.h>
+#include <unistd.h>
+
+volatile pid_t childpid = 0;
+
+void signal_handler(int sig){
+	printf("PID %zd got signal %d, die\n", getpid(), sig);
+	if(childpid)
+		kill(childpid, SIGTERM);
+	exit(sig);
+}
+
+pid_t create_child(){
+	int i;
+	pid_t p = fork();
+	if(p == 0){
+		prctl(PR_SET_PDEATHSIG, SIGTERM); // send SIGTERM to child when parent dies
+		printf("child\n");
+		sleep(1);
+	}
+	return p;
+}
+
+int main(){
+	int i = 0;
+	signal(SIGTERM, signal_handler);  // kill (-15)
+	signal(SIGINT, signal_handler);   // ctrl+C
+	signal(SIGQUIT, signal_handler);  // ctrl+\  .
+	signal(SIGTSTP, SIG_IGN);         // ctrl+Z
+	signal(SIGSEGV, signal_handler);
+	printf("my PID: %zd\n", getpid());
+	while(1){
+		childpid = create_child();
+		if(childpid){
+			printf("child #%d with PID %d\n", ++i, childpid);
+			wait(NULL);
+			printf("died\n");
+		}else return 0;
+	}
+	return 0;
+}