clocks(2)							System Calls Manual							 clocks(2)

NAME

       clock_settime(), clock_gettime(), clock_getres() - clock operations

SYNOPSIS

DESCRIPTION

   clock_settime()
       The  function  sets the specified clock, to the value specified by Time values that are between two consecutive non-negative integer multi-
       ples of the resolution of the specified clock are truncated down to the smaller multiple of the resolution.

   clock_gettime()
       The function returns the current value for the specified clock,

   clock_getres()
       The resolution of any clock can be obtained by calling Clock resolutions are implementation defined and are not settable by a process.	If
       the  argument is not NULL, the resolution of the specified clock is stored into the location pointed to by If is NULL, the clock resolution
       is not returned.

       A clock may be system wide, that is, visible to all processes; or per-process, measuring time that is meaningful only within a process.

       The following clocks are supported:

	      This clock represents the realtime clock for the system.
			  For this clock, the values returned by and specified by represent the amount of time (in seconds and nanoseconds)  since
			  the  Epoch.	It is a system wide clock.  The privilege is required to set this clock.  Processes owned by the superuser
			  have this privilege.	Processes owned by other users may have this privilege, depending on  system  configuration.   See
			  privileges(5) for more information about privileged access on systems that support fine-grained privileges.

	      This clock represents the amount of time (in seconds and nanoseconds)
			  that	the  calling process has spent executing code in the user's context.  It is a per-process clock.  It cannot be set
			  by the user.

	      This clock represents the amount of time (in seconds and nanoseconds)
			  that the calling process has spent executing code in both the user's context and in the operating system  on	behalf	of
			  the calling process.	It is a per-process clock.  It cannot be set by the user.

	      These clocks are high resolution hardware clocks
			  present  on HP-RT realtime systems.  It is included here so that applications accessing this hardware can be compiled on
			  HP-UX systems and then ported to an HP-RT target.  HP-UX does not support or

RETURN VALUE

       A return of zero indicates that the call succeeded.  A return value of -1 indicates that an error occurred, and	is  set  to  indicate  the
       error.

ERRORS

       If any of the following conditions occur, the and functions return -1 and set (see errno(2)) to the corresponding value:

	      The functions
			  and are not supported by this implementation.

	      The	  argument does not specify a known clock.

	      The	  argument to is outside the range for the given

	      The	  argument specified a nanosecond value less than zero or greater than or equal to 1000 million.

	      The requesting process does not have the necessary privileges to set the
			  specified clock.

	      The	  or argument points to an invalid address.

EXAMPLES

       Advance the system wide realtime clock approximately one hour:

       Get the resolution of the user profiling clock:

AUTHOR

       and were derived from the proposed IEEE POSIX P1003.4 Standard, Draft 14.

SEE ALSO

       timers(2), privileges(5).

STANDARDS CONFORMANCE

																	 clocks(2)