From: Serkan Coban (scobanx@yahoo.com)
Date: Wed 17 Aug 2005 - 09:46:25 EEST
man nanosleep ciktisi umarim isinizi gorur.
NANOSLEEP(2) Linux Programmer's Manual NANOSLEEP(2)
NAME
nanosleep - pause execution for a specified time
SYNOPSIS
#include <time.h>
int nanosleep(const struct timespec *req, struct
timespec
*rem);
DESCRIPTION
nanosleep delays the execution of the program for at
least
the time specified in *req. The function can return
ear-
lier if a signal has been delivered to the process. In
this case, it returns -1, sets errno to EINTR, and
writes
the remaining time into the structure pointed to by
rem
unless rem is NULL. The value of *rem can then be used
to
call nanosleep again and complete the specified pause.
The structure timespec is used to specify intervals of
time with nanosecond precision. It is specified in
<time.h> and has the form
struct timespec
{
time_t tv_sec; /* seconds */
long tv_nsec; /* nanoseconds */
};
The value of the nanoseconds field must be in the
range 0
to 999 999 999.
Compared to sleep(3) and usleep(3), nanosleep has the
advantage of not affecting any signals, it is
standardized
by POSIX, it provides higher timing resolution, and it
allows to continue a sleep that has been interrupted
by a
signal more easily.
ERRORS
In case of an error or exception, the nanosleep system
call returns -1 instead of 0 and sets errno to one of
the
following values:
EINTR The pause has been interrupted by a non-blocked
signal that was delivered to the process. The
remaining sleep time has been written into *rem so
that the process can easily call nanosleep again
and continue with the pause.
EINVAL The value in the tv_nsec field was not in the
range 0 to 999 999 999 or tv_sec was negative.
BUGS
The current implementation of nanosleep is based on
the
normal kernel timer mechanism, which has a resolution
of
1/HZ s (i.e, 10 ms on Linux/i386 and 1 ms on
Linux/Alpha).
Therefore, nanosleep pauses always for at least the
speci-
fied time, however it can take up to 10 ms longer than
specified until the process becomes runnable again.
For
the same reason, the value returned in case of a
delivered
signal in *rem is usually rounded to the next larger
mul-
tiple of 1/HZ s.
As some applications require much more precise pauses
(e.g., in order to control some time-critical
hardware),
nanosleep is also capable of short high-precision
pauses.
If the process is scheduled under a real-time policy
like
SCHED_FIFO or SCHED_RR, then pauses of up to 2 ms will
be
performed as busy waits with microsecond precision.
CONFORMING TO
POSIX.1b (formerly POSIX.4).
SEE ALSO
sleep(3), usleep(3), sched_setscheduler(2), and
timer_cre-
ate(2).
--- "Omer F. USTA" <usta@bilisimlab.com> wrote:
> Merhabalar
>
> izledi�im yöntem �u �ekilde
> while(1)
> {
>
> outb(1,base);
> for(i=0;i<=1;i++)
> {
> }
> outb(0,base);
> for(i=0;i<=1;i++)
> {
> }
> }
>
> ve bu kod ile 4 mikro saniye aralıklı pulse
> olu�turuyorum.
> benim ihtiyacım ise bunu 500~900 nanosaniye
> civarına çekmek.
>
> Hocalarım ilgilenirse sevinirim
>
> �mer F. USTA
>
>
> > _______________________________________________
> Linux-programlama mailing list
> Linux-programlama@liste.linux.org.tr
>
http://liste.linux.org.tr/mailman/listinfo/linux-programlama
>
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