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TIMES
!!!TIMES
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
NOTE
CONFORMING TO
HISTORICAL NOTES
SEE ALSO
----
!!NAME


times - get process times
!!SYNOPSIS


__#include __


__clock_t times(struct tms
*__''buf''__);__
!!DESCRIPTION


The __times__() function stores the current process times
in the __struct tms__ that ''buf'' points to. The
''struct tms'' is as defined in
'''':


struct tms {
clock_t tms_utime;  /* user time */
clock_t tms_stime;  /* system time */
clock_t tms_cutime; /* user time of children */
clock_t tms_cstime; /* system time of children */
};
The ''tms_utime'' field contains the CPU time spent executing instructions of the calling process. The ''tms_stime'' field contains the CPU time spent in the system while executing tasks on behalf of the calling process. The ''tms_cutime'' field contains the sum of the ''tms_utime'' and ''tms_cutime'' values for all waited-for terminated children. The ''tms_cstime'' field contains the sum of the ''tms_stime'' and ''tms_cstime'' values for all waited-for terminated children.


Times for terminated children (and their descendants) is
added in at the moment wait(2) or __waitpid(2)__
returns their process ID. In particular, times of
grandchildren that the children did not wait for are never
seen.


All times reported are in clock ticks.
!!RETURN VALUE


The function __times__ returns the number of clock ticks
that have elapsed since an arbitrary point in the past. For
Linux this point is the moment the system was booted. This
return value may overflow the possible range of type
clock_t. On error, (clock_t) -1 is returned, and
''errno'' is set appropriately.
!!NOTE


The number of clock ticks per second can be obtained
using


sysconf(_SC_CLK_TCK);


In POSIX-1996 the symbol CLK_TCK (defined in
'''') is mentioned as obsolescent. It is
obsolete now.


Note that clock(3) returns values of type clock_t
that are not measured in clock ticks but in
CLOCKS_PER_SEC.
!!CONFORMING TO


SVr4, SVID, POSIX, X/OPEN, BSD 4.3
!!HISTORICAL NOTES


SVr1-3 returns __long__ and the struct members are of
type __time_t__ although they store clock ticks, not
seconds since the epoch. V7 used __long__ for the struct
members, because it had no type __time_t__
yet.


On older systems the number of clock ticks per second is
given by the variable HZ.
!!SEE ALSO


time(1), getrusage(2), wait(2),
clock(3), sysconf(3)
----

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Last edited on Tuesday, June 4, 2002 12:23:48 am by "perry"

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