int main(void)
{
char c;
pid_t cpid;
pr_ids("parent");
if ( (cpid = fork()) < 0) {
printf("fork error\n");
perror(NULL);
exit(1);
}
else if (cpid > 0) {
sleep(5);
exit(0);
}
pr_ids("child");
signal(SIGHUP, sig_hup);
kill(getpid(), SIGTSTP);
pr_ids("child");
if (read(STDIN_FILENO, &c, 1) != 1) {
printf("read error from control terminal\n");
perror(NULL);
exit(1);
}
printf("read %c from stdin\n", c);
exit(0);
}
int main(int argc, char const *argv[])
{
pid_t pid;
int status;
if ((pid = fork()) < 0)
{
perror("fork error");
return -1;
}
else if (0 == pid)
{
printf("Child process\n");
pr_ids("child");
sleep(5);
exit(EXIT_SUCCESS);
}
else
{
printf("Parent Process before waiting\n");
waitpid(pid,&status,WUNTRACED); // block
printf("Parent Process After waiting\n");
printf("Parent process\n");
pr_ids("Parent");
}
return 0;
}
int main(int argc, char* argv[])
{
char c;
pid_t pid;
pr_ids("parent:");
if((pid = fork()) < 0)
{
printf("fork error");
}
else if(pid > 0)
{
sleep(5);
exit(0);
}
else
{
pr_ids("child:");
signal(SIGHUP,sig_hup);
kill(getpid(),SIGTSTP);
pr_ids("child:");
if(read(STDIN_FILENO, &c, 1) != 1)
{
printf("read error from controlling TTY, errno = %d\n",errno);
exit(0);
}
}
}
int
main(void)
{
char c;
pid_t pid;
pr_ids("parent");
if ((pid = fork()) < 0)
{
perror("fork error");
exit(1);
}
else if (pid > 0)
{ /* parent */
sleep(2); /*sleep to let child stop itself */
exit(0); /* then parent exits */
}
else { /* child */
pr_ids("child");
signal(SIGHUP, sig_hup); /* establish signal handler, to prove the orphan process will recieve the SIGHUP sig */
kill(getpid(), SIGTSTP); /* stop ourself, to prove the orphan process will recieve the SIGCONT sig */
sleep(1);
pr_ids("child"); /* prints only if we're continued, ppid should change to 1*/
if (read(STDIN_FILENO, &c, 1) != 1)
printf("read error from controlling TTY, errno = %d\n", errno); /*the orphan process is in the backgroud so can not read stdin*/
while(1)
{
printf("in the child\n");
sleep(2);
}
exit(0);
}
}
int main(void)
{
char c;
pid_t cpid;
pr_ids("parent");
if ( (cpid = fork()) < 0) {
printf("fork error\n");
perror(NULL);
exit(1);
}
else if (cpid > 0) {
if (setsid() < 0) {
printf("setsid error\n");
perror(NULL);
exit(1);
}
sleep(1);
exit(0);
}
pr_ids("child");
sleep(1);
setsid();
pr_ids("child");
exit(0);
}
int main(int argc,char **argv){
char c;
pid_t pid;
pr_ids("parent");
if((pid=fork())<0){
err_sys("fork error");
}else if(pid>0){
sleep(5);
}else{
pr_ids("child");
signal(SIGHUP, sig_up);
kill(getpid(),SIGTSTP);
pr_ids("child");
if(read(STDIN_FILENO,&c,1)!=1){
printf("read error %d on controlling TTY\n",errno);
}
}
exit(0);
}
int main()
{
char c;
pid_t pid;
pr_ids("parent");
if ( (pid = fork()) < 0 )
err_sys("fork error");
else if ( pid > 0 )
sleep(5);
else
{
pr_ids("child");
signal(SIGHUP, sig_hup);
kill(getpid(), SIGTSTP);
pr_ids("child");
if ( read(STDIN_FILENO, &c, 1) != 1 )
printf("read error %d on controlling TTY\n", errno);
}
return 0;
}
int
main(void)
{
char c;
pid_t pid;
pr_ids("parent");
if ((pid = fork()) < 0) {
err_sys("fork error");
} else if (pid > 0) { /* parent */
sleep(5); /* sleep to let child stop itself */
} else { /* child */
pr_ids("child");
signal(SIGHUP, sig_hup); /* establish signal handler */
kill(getpid(), SIGTSTP); /* stop ourself */
pr_ids("child"); /* prints only if we're continued */
if (read(STDIN_FILENO, &c, 1) != 1)
printf("read error %d on controlling TTY\n", errno);
}
exit(0);
}
int main()
{
char c;
pid_t pid;
pr_ids("parents");
pid=fork();
if(pid<0)
err_sys("fork error");
else if(pid>0)
sleep(5);
else
{
pr_ids("child");
signal(SIGHUP,sig_hup);//设置挂断信号SIGHUP消息和消息响应函数
kill(getpid(),SIGTSTP);
pr_ids("child");
if(read(STDIN_FILENO,&c,1)!=1)
printf("read error %d on controlling TTY\n",errno);
}
exit(0);
}
void
pr_tree(py_tree *tree)
{
if (tree == NULL)
return;
//printf("good\n");
for (int i = 0; i < LEN; i++) {
if (tree->next[i] != NULL) {
printf("%d\n", i);
pr_tree(tree->next[i]);
}
}
pr_ids(tree->ids);
}
