signals issue

[coder_gus]

Hello! I have recently began to program in UNIX environments and I am currently reading about signals.So i tried a snippet that seems it doesn't do what i intended to.So i want to print the counter i from a for loop until a value is reached, than stop the process.Instead i get the process killed without any output.

1 #include <stdio.h>
  2 #include <sys/types.h>
  3 #include <unistd.h>
  4 #include <signal.h>
  5
  6 int main()
  7 {
  8         pid_t my_pid;
  9
 10         my_pid=getpid();
 11
 12         int i;
 13         for (i=0;i<30;i++)
 14         {
 15
 16                 fprintf(stdout,"%d ",i);
 17                 if (i==20)
 18                         kill(my_pid,SIGSTOP);
 19         }
 20
 21         return 0;
 22 }

Any help is more then welcome.Thank you.

[WaltP]

Try adding fflush(stdout); immediately after your fprintf() .

Linux is probably buffering the output, so the display waits until the output buffer is full before displaying the data. But it never gets filled because of the kill() . fflush(stdout) will force the buffer to be displayed and cleared.

[coder_gus]

Try adding fflush(stdout); immediately after your fprintf() .

Linux is probably buffering the output, so the display waits until the output buffer is full before displaying the data. But it never gets filled because of the kill() . fflush(stdout) will force the buffer to be displayed and cleared.

That worked well.
Thanks a lot WaltP.

[WaltP]

Anytime. Oh, and by the way, when you post code, don't post with line numbers. If we want to test the code it's difficult.

And good code formatting, too.