clock-0.4: High-resolution clock functions: monotonic, realtime, cputime.

Safe HaskellSafe-Inferred

System.Clock

Description

High-resolution, realtime clock and timer functions for Posix systems. This module is being developed according to IEEE Std 1003.1-2008: http://www.opengroup.org/onlinepubs/9699919799/, http://www.opengroup.org/onlinepubs/9699919799/functions/clock_getres.html#

Synopsis

Documentation

data Clock Source

Clock types. A clock may be system-wide (that is, visible to all processes) or per-process (measuring time that is meaningful only within a process). All implementations shall support CLOCK_REALTIME.

Constructors

Monotonic

The identifier for the system-wide monotonic clock, which is defined as a clock measuring real time, whose value cannot be set via clock_settime and which cannot have negative clock jumps. The maximum possible clock jump shall be implementation-defined. For this clock, the value returned by getTime represents the amount of time (in seconds and nanoseconds) since an unspecified point in the past (for example, system start-up time, or the Epoch). This point does not change after system start-up time. Note that the absolute value of the monotonic clock is meaningless (because its origin is arbitrary), and thus there is no need to set it. Furthermore, realtime applications can rely on the fact that the value of this clock is never set.

Realtime

The identifier of the system-wide clock measuring real time. For this clock, the value returned by getTime represents the amount of time (in seconds and nanoseconds) since the Epoch.

ProcessCPUTime

The identifier of the CPU-time clock associated with the calling process. For this clock, the value returned by getTime represents the amount of execution time of the current process.

ThreadCPUTime

The identifier of the CPU-time clock associated with the calling OS thread. For this clock, the value returned by getTime represents the amount of execution time of the current OS thread.

data TimeSpec Source

TimeSpec structure

Constructors

TimeSpec !Int !Int 

Instances

getTime :: Clock -> IO TimeSpecSource

The getTime function shall return the current value for the specified clock.

getRes :: Clock -> IO TimeSpecSource

The getRes function shall return the resolution of any clock. Clock resolutions are implementation-defined and cannot be set by a process.

sec :: TimeSpec -> IntSource

Gets seconds of a timespec value.

nsec :: TimeSpec -> IntSource

Gets nanoseconds of a timespec value.