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Full Discussion: Nanosleep in signal call
Top Forums Programming Nanosleep in signal call Post 302963439 by mattdj on Wednesday 30th of December 2015 12:41:57 PM
Old 12-30-2015
Nanosleep in signal call
Hi @ll Smilie

I have a problem with my code but first a short description:

1. I have one signal call SIGUSR1
2. In the signal I try to use nanosleep and now:

When I put kill -SIGUSR1 pid --> sometimes works fine, sometimes returns me an error with ,,Interrupt system call", sometimes I got error with "Success". Why? What mistake did I make? How to improve that?

My code:

Code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <time.h>

void handler_signal(int signal)
{
   const char *signal_name;
   sigset_t pending; // syngaly oczekujace
   int losowy_czas ;  
   struct timespec ts; 
   int ret; 
   
   
   losowy_czas = rand() % 15 + 5;  
   ts.tv_sec = 0; 
   ts.tv_nsec = losowy_czas * 100000000;
   
   ret = clock_nanosleep(CLOCK_MONOTONIC,0,&ts,NULL); 

   if(ret)
	perror("Blad funkcji clock_nanosleep");   	


   switch(signal)
   {
   	case SIGUSR1:
		signal_name = "SIGUSR1"; 
		break;
	default:
		fprintf(stderr,"Zlapany zly sygnal: %d \n", signal); 
		return; 
  }

  //unsafe I know ! 
  printf("To ja - sygnal ! %s Wylosowany czas %d \n", signal_name,losowy_czas);  

}
int main(int argc, char *argv[])
{
   int i; 
   char *endptr; 
 
   struct sigaction sa; 	
 
  
   srand((unsigned int) time(NULL)); 
   /*     PROCES P    */


   sa.sa_handler = &handler_signal;
   sa.sa_flags = SA_RESTART; 
   
   sigfillset(&sa.sa_mask); 
   
   if(sigaction(SIGUSR1,&sa,NULL) == -1)
   {
	perror("Nie mozna obsluzyc SIGUSR1");	
   }

   
   for(i=0; i<2000; i++)
   {
     printf("Running %i \n", i);
     sleep(1); 
   }  

   return;
}

Last edited by Scrutinizer; 12-30-2015 at 02:33 PM.. Reason: Spelling
 

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LEARN ABOUT MOJAVE

kill

KILL(1) 						    BSD General Commands Manual 						   KILL(1)

NAME

     kill -- terminate or signal a process

SYNOPSIS

     kill [-s signal_name] pid ...
     kill -l [exit_status]
     kill -signal_name pid ...
     kill -signal_number pid ...

DESCRIPTION

     The kill utility sends a signal to the processes specified by the pid operands.

     Only the super-user may send signals to other users' processes.

     The options are as follows:

     -s signal_name
	     A symbolic signal name specifying the signal to be sent instead of the default TERM.

     -l [exit_status]
	     If no operand is given, list the signal names; otherwise, write the signal name corresponding to exit_status.

     -signal_name
	     A symbolic signal name specifying the signal to be sent instead of the default TERM.

     -signal_number
	     A non-negative decimal integer, specifying the signal to be sent instead of the default TERM.

     The following PIDs have special meanings:

     -1      If superuser, broadcast the signal to all processes; otherwise broadcast to all processes belonging to the user.

     Some of the more commonly used signals:

     1	     HUP (hang up)
     2	     INT (interrupt)
     3	     QUIT (quit)
     6	     ABRT (abort)
     9	     KILL (non-catchable, non-ignorable kill)
     14      ALRM (alarm clock)
     15      TERM (software termination signal)

     Some shells may provide a builtin kill command which is similar or identical to this utility.  Consult the builtin(1) manual page.

EXIT STATUS

     The kill utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

     Terminate the processes with PIDs 142 and 157:

	   kill 142 157

     Send the hangup signal (SIGHUP) to the process with PID 507:

	   kill -s HUP 507

SEE ALSO

     builtin(1), csh(1), killall(1), ps(1), sh(1), kill(2), sigaction(2)

STANDARDS

     The kill utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

HISTORY

     A kill command appeared in Version 3 AT&T UNIX.

BUGS

     A replacement for the command ``kill 0'' for csh(1) users should be provided.

BSD
								  April 28, 1995							       BSD
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