system_clock
- Date:
02-06-2023
NAME
SYSTEM_CLOCK - Returns numeric data from a real-time clock
SYNOPSIS
CALL SYSTEM_CLOCK ([[COUNT=]count][,[COUNT_RATE=]count_rate]
[,[COUNT_MAX=count_max])
INTEGER :: count, count_max
INTEGER|REAL :: count_rate
STANDARDS
Fortran 2008
DESCRIPTION
The SYSTEM_CLOCK intrinsic subroutine returns information gathered from the real-time clock. SYSTEM_CLOCK accepts the following arguments:
- count
Must be scalar and type integer.
If count is present, it is set to a machine-specific value based on the current value of the machine’s clock.
If there is no clock, it is set to -HUGE(0).
If count is type integer (KIND=8), the machine-specific value is incremented by one for each clock count until the value count_max is reached; it is reset to 0 at the next count.
If count is type integer (KIND=4), the machine-specific value is incremented by one for every 100 clock counts until the value count_max is reached; it is reset to 0 at the next count.
If there is a clock, it lies in the range 0 to count_max.
- count_rate
Must be scalar and type integer or real.
If count_rate is present, it is set to the number of clock counts per second.
If there is no clock, it is set to 0.
If count_rate is type integer (KIND=4) or real (KIND=4), the rate is scaled down by a factor of 100.
- count_max
Must be scalar and type integer.
If count_max is present, it is set to the maximum value that count can have.
If there is no clock, it is set to 0.
Because the values of count reach the count_max in a very short time for KIND=4 (32-bit) types, the value is scaled down by a factor of 100. The KIND=4 count_rate is scaled by the same factor. Because of this scaling, care must be taken to ensure that the kind types for count and count_rate are the same. Since the Fortran 2008 Standard has no restriction concerning kind types for these arguments, the scaling can be disabled by using the ftn command line -ds option. See the ftn(1) man page for details on using this argument.
The name of this intrinsic cannot be passed as an argument.
SEE ALSO
ftn(1)
sysclock(3f)
gettimeofday(2)