Safe Haskell	Safe
Language	Haskell98

System.Clock

Description

High-resolution, realtime clock and timer functions for Posix

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. (The only suspend-aware monotonic is CLOCK_BOOTTIME on Linux.)

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.
MonotonicRaw	(since Linux 2.6.28; Linux-specific) Similar to CLOCK_MONOTONIC, but provides access to a raw hardware-based time that is not subject to NTP adjustments or the incremental adjustments performed by adjtime(3).
Boottime	since Linux 2.6.39; Linux-specific) Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended. This allows applications to get a suspend-aware monotonic clock without having to deal with the complications of CLOCK_REALTIME, which may have discontinuities if the time is changed using settimeofday(2).
MonotonicCoarse	(since Linux 2.6.32; Linux-specific) A faster but less precise version of CLOCK_MONOTONIC. Use when you need very fast, but not fine-grained timestamps.
RealtimeCoarse	(since Linux 2.6.32; Linux-specific) A faster but less precise version of CLOCK_REALTIME. Use when you need very fast, but not fine-grained timestamps.

Instances

Enum Clock Source
Eq Clock Source
Read Clock Source
Show Clock Source
Generic Clock Source
type Rep Clock Source

data TimeSpec Source

TimeSpec structure

Constructors

TimeSpec
Fields sec :: !Int64 seconds nsec :: !Int64 nanoseconds

Instances

Eq TimeSpec Source
Num TimeSpec Source
Ord TimeSpec Source
Read TimeSpec Source
Show TimeSpec Source
Generic TimeSpec Source
Storable TimeSpec Source
type Rep TimeSpec Source

getTime :: Clock -> IO TimeSpec Source

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

getRes :: Clock -> IO TimeSpec Source

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

diffTimeSpec :: TimeSpec -> TimeSpec -> TimeSpec Source

Compute the absolute difference.

timeSpecAsNanoSecs :: TimeSpec -> Integer Source

TimeSpec as nano seconds.