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(g77-295.info)System_Clock Intrinsic

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System_Clock Intrinsic
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     CALL System_Clock(COUNT, RATE, MAX)

COUNT: `INTEGER(KIND=1)'; scalar; INTENT(OUT).

RATE: `INTEGER(KIND=1)'; OPTIONAL; scalar; INTENT(OUT).

MAX: `INTEGER(KIND=1)'; OPTIONAL; scalar; INTENT(OUT).

Intrinsic groups: `f90'.

Description:

   Returns in COUNT the current value of the system clock; this is the
value returned by the UNIX function `times(2)' in this implementation,
but isn't in general.  RATE is the number of clock ticks per second and
MAX is the maximum value this can take, which isn't very useful in this
implementation since it's just the maximum C `unsigned int' value.

   On some systems, the underlying timings are represented using types
with sufficiently small limits that overflows (wraparounds) are
possible, such as 32-bit types.  Therefore, the values returned by this
intrinsic might be, or become, negative, or numerically less than
previous values, during a single run of the compiled program.