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gettimeofday(2) [hpux man page]

gettimeofday(2) 						System Calls Manual						   gettimeofday(2)

NAME
gettimeofday - get the date and time SYNOPSIS
DESCRIPTION
The function obtains the current time, expressed as seconds and microseconds since Epoch, and stores it in the structure pointed to by tp. The resolution of the system clock is one microsecond. PARAMETERS
Programs should use this time zone information only in the absence of the environment variable. tp A pointer to a structure in which the current time is returned. The structure includes the following members: tzp If this parameter is not a null pointer, it is interpreted as a pointer to a structure under HP-UX. The structure has the following fields: tz_minuteswest The number of minutes that the local time zone is west of Coordinated Universal Time (UTC) or Epoch. tz_dsttime A flag that, if nonzero, indicates that Daylight Savings Time (DST) applies locally during the appropriate part of the year. RETURN VALUE
returns the following values under HP-UX: Successful completion. Failure. is set to indicate the error. ERRORS
If fails, is set to the following value under HP-UX: [EFAULT] An argument address referenced invalid memory. EXAMPLES
The following HP-UX example calls twice. It then computes the lapsed time between the calls in seconds and microseconds and stores the result in a timeval structure: WARNINGS
Relying on a granularity of one microsecond may result in code that is not portable to other platforms. AUTHOR
was developed by the University of California, Berkeley, and HP. SEE ALSO
date(1), ftime(2), settimeofda(2), stime(2), time(2), ctime(3C). gettimeofday(2)

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GETTIMEOFDAY(2) 					      BSD System Calls Manual						   GETTIMEOFDAY(2)

NAME
gettimeofday, settimeofday -- get/set date and time SYNOPSIS
#include <sys/time.h> int gettimeofday(struct timeval *restrict tp, void *restrict tzp); int settimeofday(const struct timeval *tp, const 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 settimeofday() call. The time is expressed in seconds and microseconds since midnight (0 hour), January 1, 1970. The resolution of the sys- tem clock is hardware dependent, and the time may be updated continuously or in ``ticks.'' If tp is NULL and tzp is non-NULL, gettimeofday() will populate the timezone struct in tzp. If tp is non-NULL and tzp is NULL, then only the timeval struct in tp is populated. If both tp and tzp are NULL, nothing is returned. The structures pointed to by tp and tzp are defined in <sys/time.h> as: struct timeval { time_t tv_sec; /* seconds since Jan. 1, 1970 */ suseconds_t tv_usec; /* and microseconds */ }; struct timezone { int tz_minuteswest; /* of Greenwich */ int tz_dsttime; /* type of dst correction to apply */ }; The timeval structure specifies a time value in seconds and microseconds. The values in timeval are opaque types whose length may vary on different machines; depending on them to have any given length may lead to errors. 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. If the system securelevel is greater than 1 (see init(8) ), the time may only be advanced. This limitation is imposed to prevent a malicious super-user from setting arbitrary time stamps on files. The system time can still be adjusted backwards using the adjtime(2) system call even when the system is secure. 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. LEGACY SYNOPSIS
#include <sys/time.h> int gettimeofday(struct timeval *tp, struct timezone *tzp); The type of tzp has changed. SEE ALSO
date(1), adjtime(2), ctime(3), compat(5), timed(8) HISTORY
The gettimeofday() function call appeared in 4.2BSD. 4th Berkeley Distribution August 5, 2008 4th Berkeley Distribution

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