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CRTL, clock_settime
*Conan The Librarian
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Sets the specified clock.
This function is supported on OpenVMS Integrity servers and
Alpha only.
Format
#include <time.h>
int clock_settime (clockid_t clock_id, const struct timespec *tp);
clock_id
The clock type used for the clock that is to be set. The CLOCK_
REALTIME clock is supported and represents the TIME-OF-DAY clock
for the system.
tp
A pointer to a timespec data structure.
The clock_settime function sets the specified clock, clock_id,
to the value specified by tp. Time values that are between two
consecutive non-negative integer multiples of the resolution of
the specified clock are truncated down to the smaller multiple of
the resolution.
A clock can be systemwide (that is, visible to all processes)
or per-process (measuring time that is meaningful only within a
process).
The CLOCK_REALTIME clock, defined in <time.h>, represents the
realtime clock for the system. For this clock, the values
specified by clock_settime and returned by clock_gettime
represent the amount of time elapsed, in seconds and nanoseconds,
since the Epoch. The Epoch is defined as 00:00:00:00 January 1,
1970 Greenwich Mean Time (GMT).
You must have OPER, LOG_IO, and SYSPRV privileges to use the
clock_settime function.
On success, the function returns 0.
On failure, the function returns -1 and sets errno to indicate
the error.
See also clock_getres, clock_gettime, time, and ctime.
0 Indicates success.
-1 Indicates failure; errno is set to the
following value:
o EINVAL - The clock_id argument does not
specify a known clock, or the tp argument
is outside the range for the given clock_id
or specifies a nanosecond value less than 0
or greater than or equal to 1 billion.
o EPERM - The requesting process does not
have the appropriate privilege to set the
specified clock.