nanosleep mystery

[chandanlinster]

Hi,
I executed the following code on slackware 10.2 (with 2.6.22 kernel)
and ubuntu 7.10 (again with 2.6.22 kernel).
On slackware, the value of "diff" is sometimes 0(zero). On ubuntu it
is consistently above 1(one). Can anybody tell me why this may be
happening??

/***************** Code listing ****************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <sys/times.h>

int main(int argc, char *argv[])
{
clock_t t1, t2, diff;
struct timespec req_time, rem_time;

req_time.tv_sec = 0;
req_time.tv_nsec = atol(argv[1]);

do {
if ((t1 = times(NULL)) == (clock_t)(-1)) {
perror("times");
exit(1);
}

if (nanosleep(&req_time, &rem_time) == -1) {
perror("nanosleep");
exit(1);
}

if ((t2 = times(NULL)) == (clock_t)(-1)) {
perror("times");
exit(1);
}

diff = t2 - t1;

printf("diff = %ld\n", diff);
} while (1);

return 0;
}

 

[Kenny McCormack]

Hi,
I executed the following code on slackware 10.2 (with 2.6.22 kernel)
and ubuntu 7.10 (again with 2.6.22 kernel).
On slackware, the value of "diff" is sometimes 0(zero). On ubuntu it
is consistently above 1(one). Can anybody tell me why this may be
happening??

Off topic, blah, blah, blah.

We all know the drill by now.

 

[Mark Bluemel]

Hi,
I executed the following code on slackware 10.2 (with 2.6.22 kernel)
and ubuntu 7.10 (again with 2.6.22 kernel).
On slackware, the value of "diff" is sometimes 0(zero). On ubuntu it
is consistently above 1(one). Can anybody tell me why this may be
happening??

Ask on a newsgroup related to those operating systems. This is not
something that is actually related to the C language.

As nanosleep is a POSIX function, comp.unix.programmer may be a suitable
place to raise the question. Alternatively, as this relates to Linux
systems in particular, one of the Linux newsgroups may be better.

 

[CBFalconer]

I executed the following code on slackware 10.2 (with 2.6.22
kernel) and ubuntu 7.10 (again with 2.6.22 kernel). On slackware,
the value of "diff" is sometimes 0(zero). On ubuntu it is
consistently above 1(one). Can anybody tell me why this may be
happening??
.... snip ...

printf("diff = %ld\n", diff);
} while (1);

return 0;
}

diff is a clock_t. What does printf desire for a %ld descriptor|?