SIGTERM

SIGTERM

[Bubulac Tatiana]

Hi,

    I want to terminate a parent process that attach several shared
memory segments
with kill(pid, SIGTERM) but it fails to terminate.
    Even if I give the command from command line it fails to terminate.
    If I give kill -9 pid it terminates but the shred memory segments
remains.
    Why I cannot terminate it with  SIGTERM signal?

    "....
    status = kill ((pid_t)pid, SIGTERM);
     printf("status = %d\n", status);
    ...."
The status is 0. The pid is correct.

TIA,
Bubulac Tatiana.

Re: SIGTERM

[Glynn Clements]

Bubulac Tatiana wrote:

>     I want to terminate a parent process that attach several shared
> memory segments
> with kill(pid, SIGTERM) but it fails to terminate.
>     Even if I give the command from command line it fails to terminate.
>     If I give kill -9 pid it terminates but the shred memory segments
> remains.
>     Why I cannot terminate it with  SIGTERM signal?

Presumably the receiver has either blocked, ignored or caught SIGTERM.

>     "....
>     status = kill ((pid_t)pid, SIGTERM);
>      printf("status = %d\n", status);
>     ...."
> The status is 0. The pid is correct.

That only tells you that the signal was sent. It doesn't tell you what
the receiving process did as a result; the receiving process may not
have even received the signal by the time that kill() returns.

-- 
Glynn Clements <glynn.clements@virgin.net>

Re: SIGTERM

[Bubulac Tatiana]

That's right.

In the parent process I have the  line no 6 where it blocks.

...
1     signal (SIGTERM, die);
2     signal (SIGALRM, dummy);
...
3    for (min = 0; min < 15 && not_done; min++)
4    {
5         alarm ((unsigned int) 60); /* wait for 1 minute */
6         pid = wait (&status);    /* Wait for a process to end */
7         alarm ((unsigned int) 0); /* Reset alarm */
....
8    }

The problem is that the child process did not catch the signal. I put a
printf in the child signal handler
function.
If I give the "kill child_pid" also nothing happens. Of course if I give
"kill -9 child_pid" the child is killed
and the parent will display "Normal termination".


Glynn Clements wrote:

> Bubulac Tatiana wrote:
>
> >     I want to terminate a parent process that attach several shared
> > memory segments
> > with kill(pid, SIGTERM) but it fails to terminate.
> >     Even if I give the command from command line it fails to terminate.
> >     If I give kill -9 pid it terminates but the shred memory segments
> > remains.
> >     Why I cannot terminate it with  SIGTERM signal?
>
> Presumably the receiver has either blocked, ignored or caught SIGTERM.
>
> >     "....
> >     status = kill ((pid_t)pid, SIGTERM);
> >      printf("status = %d\n", status);
> >     ...."
> > The status is 0. The pid is correct.
>
> That only tells you that the signal was sent. It doesn't tell you what
> the receiving process did as a result; the receiving process may not
> have even received the signal by the time that kill() returns.
>
> --
> Glynn Clements <glynn.clements@virgin.net>

Re: SIGTERM

[Glynn Clements]

Bubulac Tatiana wrote:

> In the parent process I have the  line no 6 where it blocks.
> 
> ...
> 1     signal (SIGTERM, die);
> 2     signal (SIGALRM, dummy);
> ...
> 3    for (min = 0; min < 15 && not_done; min++)
> 4    {
> 5         alarm ((unsigned int) 60); /* wait for 1 minute */
> 6         pid = wait (&status);    /* Wait for a process to end */
> 7         alarm ((unsigned int) 0); /* Reset alarm */
> ....
> 8    }
> 
> The problem is that the child process did not catch the signal. I put a
> printf in the child signal handler
> function.
> If I give the "kill child_pid" also nothing happens.

That suggests that the child *is* catching the signal. If the child
didn't catch SIGTERM, it would die.

Try changing the child's signal handler to call fflush(), or to use
write() instead of printf().

-- 
Glynn Clements <glynn.clements@virgin.net>