Народ, как померять время в юниксе ?
man -a time ; man gettimeofday
gettimeofday
GETTIMEOFDAY(2) Linux Programmer's Manual GETTIMEOFDAY(2)
NAME
gettimeofday, settimeofday - get / set time
SYNOPSIS
#include <sys/time.h>
#include <unistd.h>
int gettimeofday(struct timeval *tv, struct timezone *tz);
int settimeofday(const struct timeval *tv , const struct timezone *tz);
DESCRIPTION
gettimeofday and settimeofday can set the time as well as a timezone. tv is a timeval struct, as specified
in /usr/include/sys/time.h:
struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
and tz is a timezone :
struct timezone {
int tz_minuteswest; /* minutes W of Greenwich */
int tz_dsttime; /* type of dst correction */
};
The use of the timezone struct is obsolete; the tz_dsttime field has never been used under Linux - it has
not been and will not be supported by libc or glibc. Each and every occurrence of this field in the kernel
source (other than the declaration) is a bug. Thus, the following is purely of historic interest.
The field tz_dsttime contains a symbolic constant (values are given below) that indicates in which part of
the year Daylight Saving Time is in force. (Note: its value is constant throughout the year - it does not
indicate that DST is in force, it just selects an algorithm.) The daylight saving time algorithms defined
are as follows :
DST_NONE /* not on dst */
DST_USA /* USA style dst */
DST_AUST /* Australian style dst */
DST_WET /* Western European dst */
DST_MET /* Middle European dst */
DST_EET /* Eastern European dst */
DST_CAN /* Canada */
DST_GB /* Great Britain and Eire */
DST_RUM /* Rumania */
DST_TUR /* Turkey */
DST_AUSTALT /* Australian style with shift in 1986 */
Of course it turned out that the period in which Daylight Saving Time is in force cannot be given by a sim╜
ple algorithm, one per country; indeed, this period is determined by unpredictable political decisions. So
this method of representing time zones has been abandoned. Under Linux, in a call to settimeofday the
tz_dsttime field should be zero.
Under Linux there is some peculiar `warp clock' semantics associated to the settimeofday system call if on
the very first call (after booting) that has a non-NULL tz argument, the tv argument is NULL and the tz_min╜
uteswest field is nonzero. In such a case it is assumed that the CMOS clock is on local time, and that it
has to be incremented by this amount to get UTC system time. No doubt it is a bad idea to use this feature.
The following macros are defined to operate on a struct timeval :
#define timerisset(tvp)\
tvp)->tv_sec || (tvp)->tv_usec)
#define timercmp(tvp, uvp, cmp)\
tvp)->tv_sec cmp (uvp)->tv_sec ||\
(tvp)->tv_sec == (uvp)->tv_sec &&\
(tvp)->tv_usec cmp (uvp)->tv_usec)
#define timerclear(tvp)\
tvp)->tv_sec = (tvp)->tv_usec = 0)
If either tv or tz is null, the corresponding structure is not set or returned.
Only the super user may use settimeofday.
RETURN VALUES
gettimeofday and settimeofday return 0 for success, or -1 for failure (in which case errno is set appropri╜
ately).
ERRORS
EPERM settimeofday is called by someone other than the superuser.
EINVAL Timezone (or something else) is invalid.
EFAULT One of tv or tz pointed outside your accessible address space.
CONFORMING TO
SVr4, BSD 4.3
SEE ALSO
date(1 adjtimex(2 time(2 ctime(3 ftime(3)
Linux 2.0.32 10 December 1997 1
Йо, спасибо.
#include <sys/time.h>
long get_time
{
struct timeval buf;
gettimeofday (&buf,0);
return buf.tv_sec*1000+buf.tv_usec/1000;
}
long print_t(long t)
{
printf("\nProcess time = %5.3f sec"doubleget_time-t/1000.0);
return get_time;
}
int main
{
long t1;
t1 = get_time;
// your process
t1 = print_t(t1); // print process time
return 0;
}
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vertyal17
Вобщем задача такая - есть момент времени перед запуском команды, а затем момент времени после запуска команды, надо узнать сколько времени прошло, показатель точности может разный быть (команда при различных параметрах выполняется разное время так что может занимать времени и минуты, и секунды.В винде было чтото типа геттайм чтоли. В юниксе есть идея чтото типа time.h но мана нету, потому я так и не понял недавно, какие функции в нем есть, сколько не ковирылся в нем (у меня мандрак 9).
Вобщем, нужна функция которая узнает настотящее время с точностью до секунд, или функция запускающая таймер какойто.
Подскажите народ, и чтоб с документацией.
язык си.