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Full Discussion: Delay a process.
Top Forums Programming Delay a process. Post 101398 by matrixmadhan on Wednesday 8th of March 2006 01:31:48 AM
Old 03-08-2006
introducing a sleep would effect the process,
either it is a foreground or background process

if you are so particular in guaranteeing 3 seconds
use sigALARM for 3 seconds

check for the following code;

Code:
# include<stdio.h>
# include<time.h>

void a();
void b();
void c();

int main()
{
  clock_t c1, c2, c3;
  c1=clock();

  (void)a();

  c2=clock();
  fprintf(stderr, "Diff returning from fun a %ld\n", c2 - c1);
  c1=clock();

  (void)b();

  c2=clock();
  fprintf(stderr, "Diff returning from fun b %ld\n", c2 - c1);
  c1=clock();
  sleep(3);

  (void)c();
  c2=clock();
  fprintf(stderr, "Diff returning from fun c %d\n", c2 - c1);
  return 0;
}

void a()
{
  int i;
  fprintf(stderr, "in a\n");
  for( i=0; i<500000; i++);
}
void b()
{
  int i;
  fprintf(stderr, "in b\n");
  for( i =0; i<200000; i++);
}
void c()
{
  int i;
  fprintf(stderr, "in c\n");
  for( i =0; i<600000; i++);
}

the above code uses clock function and hence only the real time used by the process would be affected the sleep(3) and not the cpu time.
clock function will account only for the CPU and system time and not the context switch to sleep state and hence sleep cannot track the 3 seconds

you need to use the following structure in /usr/include/sys/time.h

Code:
struct tms {
  clock_t  tms_utime;     /* user time */
  clock_t  tms_stime;     /* system time */
  clock_t  tms_cutime;    /* user time, children */
  clock_t  tms_cstime;    /* system time, children */
};

hope this helps!!!
 

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LEARN ABOUT CENTOS

pam_faildelay

PAM_FAILDELAY(8)						 Linux-PAM Manual						  PAM_FAILDELAY(8)

NAME

       pam_faildelay - Change the delay on failure per-application

SYNOPSIS

       pam_faildelay.so [debug] [delay=microseconds]

DESCRIPTION

       pam_faildelay is a PAM module that can be used to set the delay on failure per-application.

       If no delay is given, pam_faildelay will use the value of FAIL_DELAY from /etc/login.defs.

OPTIONS

       debug
	   Turns on debugging messages sent to syslog.

       delay=N
	   Set the delay on failure to N microseconds.

MODULE TYPES PROVIDED

       Only the auth module type is provided.

RETURN VALUES

       PAM_IGNORE
	   Delay was successful adjusted.

       PAM_SYSTEM_ERR
	   The specified delay was not valid.

EXAMPLES

       The following example will set the delay on failure to 10 seconds:

	   auth  optional  pam_faildelay.so  delay=10000000

SEE ALSO

       pam_fail_delay(3), pam.conf(5), pam.d(5), pam(8)

AUTHOR

       pam_faildelay was written by Darren Tucker <dtucker@zip.com.au>.

Linux-PAM Manual						    09/19/2013							  PAM_FAILDELAY(8)
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