gettimeofday(2) System Calls Manual gettimeofday(2)Name
gettimeofday, settimeofday - get or set date and time
Syntax
#include <sys/time.h>
gettimeofday(tp, tzp)
struct timeval *tp;
struct timezone *tzp;
settimeofday(tp, tzp)
struct timeval *tp;
struct timezone *tzp;
Description
The system call returns the system's notion of the current Greenwich time and the current time zone. Time returned is expressed relative
in seconds and microseconds since midnight January 1, 1970.
The structures pointed to by tp and tzp are defined in <sys/time.h> as:
struct timeval {
long tv_sec; /* seconds since Jan. 1, 1970 */
long tv_usec; /* and microseconds */
};
struct timezone {
int tz_minuteswest; /* of Greenwich */
int tz_dsttime; /* type of dst correction to apply */
};
The timezone structure indicates the local time zone (measured in minutes of time westward from Greenwich), and a flag that, if nonzero,
indicates that Daylight Saving time applies locally during the appropriate part of the year.
Only the superuser can set the time of day.
Return Values
A 0 return value indicates that the call succeeded. A -1 return value indicates an error occurred, and in this case an error code is
stored into the global variable errno.
Diagnostics
The call fails under the following conditions:
[EFAULT] An argument address referenced invalid memory.
[EPERM] A user other than the superuser attempted to set the time.
See Alsodate(1), stime(2), ctime(3)gettimeofday(2)
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GETTIMEOFDAY(2) System Calls Manual GETTIMEOFDAY(2)NAME
gettimeofday, settimeofday - get/set date and time
SYNOPSIS
#include <sys/time.h>
gettimeofday(tp, tzp)
struct timeval *tp;
struct timezone *tzp;
settimeofday(tp, tzp)
struct timeval *tp;
struct timezone *tzp;
DESCRIPTION
The system's notion of the current Greenwich time and the current time zone is obtained with the gettimeofday call, and set with the set-
timeofday call. The time is expressed in seconds and microseconds since midnight (0 hour), January 1, 1970. The resolution of the system
clock is hardware dependent, and the time may be updated continuously or in ``ticks.'' If tzp is zero, the time zone information will not
be returned or set.
The structures pointed to by tp and tzp are defined in <sys/time.h> as:
struct timeval {
long tv_sec; /* seconds since Jan. 1, 1970 */
long tv_usec; /* and microseconds */
};
struct timezone {
int tz_minuteswest; /* of Greenwich */
int tz_dsttime; /* type of dst correction to apply */
};
The timezone structure indicates the local time zone (measured in minutes of time westward from Greenwich), and a flag that, if nonzero,
indicates that Daylight Saving time applies locally during the appropriate part of the year.
Only the super-user may set the time of day or time zone.
RETURN
A 0 return value indicates that the call succeeded. A -1 return value indicates an error occurred, and in this case an error code is
stored into the global variable errno.
ERRORS
The following error codes may be set in errno:
[EFAULT] An argument address referenced invalid memory.
[EPERM] A user other than the super-user attempted to set the time.
SEE ALSO date(1), adjtime(2), ctime(3), timed(8)4th Berkeley Distribution May 14, 1986 GETTIMEOFDAY(2)
hi everyone. If you have a function created in your code and you want to find out how long it takes for it to run you can use a struct called gettimeofday().
so lets say we have a function like this
int myfunction (int r)
{
/*some math calculations*/
return answer;
}
How do i set up... (3 Replies)
Our system has an option to supply your timezone in area of world you want to keep time for user transactions and such.
It keeps time zone for user in database as for example -5 for EST.
The problem is we are in EDT -4 (daylight savings time) so the time is displayed wrong.
We can put the... (2 Replies)
Hello,
I have found a piece of code which converts seconds elapsed since 1970 for an input date. Can anyone please explain a little bit the code below:
#!/bin/bash
# function to reproduce UNIX time() value
second()
{
set -- $(TZ=GMT date '+%Y %m %d')
local y=$1 m=1$2 d=1$3
((m-=103,... (0 Replies)
i have written the code in which i want to calculate timedifference of request sent time and response receive time from device in second and microsecond. but when i executes the binary i get the response receive time earlier than request sent time which in turn returns the negative time difference.... (3 Replies)
Hi folks,
I would like to read the start date and end date of the Daylight Saving Time for the given timezone in the given year. What's the function in C/C++ to read the start of the Daylight Saving date and end of Daylight saving date?
I'm using Linux 2.6.xx Kernel.
For Example, in... (4 Replies)
Hi,
On my server timezone is IST, so I have configured the sudo for user to change the date, but when he is changing the date time zone is also getting changed from ist to gmt. using solaris 10. I have checked in /etc/TIMEZONE file in that it is showing TZ=Asia/Calcutta, wheather any other file... (1 Reply)
Hello all,
I just want to update the timezone file with new file to update the time, so the zone in /etc/TIMEZONE will be the same but the file it refers to will be changed, and the local time should be changed, can this take effect without rebooting Solaris 10? (9 Replies)