dvlopt.sysrun — dvlopt/sysrun 0.0.3

Miscellaneous system utilities.

env clj

(env)

(env variable)

Gets environment variables or one of them.

Throws

java.lang.SecurityException When not allowed.

finalize clj

(finalize)

Suggests the finalization of discarded objects not yet finalized.

The JVM makes the best effort to do it before returning.

garbage-collection clj

(garbage-collection)

Suggests to run garbarge collection.

The JVM makes the best effort to do it before returning.

line-separator clj

System-dependant line separator.

memory-allocated clj

(memory-allocated)

Amount of memory currently allocated by the JVM, in bytes.

memory-allocated-free clj

(memory-allocated-free)

Approximately the amount of free memory available relative to what is currently allocated by the JVM, in bytes.

memory-free clj

(memory-free)

Approximately the amount of available free memory the JVM can claim at most, right now, in bytes.

memory-limit clj

(memory-limit)

Maximum amount of memory the JVM will attempt to use in total, in bytes.

This is a soft limit.

memory-used clj

(memory-used)

Approximately the amount of memory currently used, in bytes.

nano-timing clj

(nano-timing)

Current time expressed in nanoseconds relative to an arbitratry origin defined by the JVM.

Deltas of values at different times provides high resolution timing.

Nanosecond resolution does NOT mean nanosecond accuracy.

Accuracy is at least as good as that of timestamp, often better.

native-name clj

(native-name lib-name)

Returns a platform-specific filename given a generic one.

Depending on the OS, native library naming usually follow a convention.

Ex. On linux, "c" => "libc.so"

on-shutdown clj

(on-shutdown action)

Registers an action (ie. no-arg function) to execute on JVM shutdown.

Returns a no-arg function for cancelling the registration.

Might throw both when adding an action and removing one.

processors clj

(processors)

Number of available processors available to the JVM.

Might change during a particular invocation of the JVM.

property clj

(property)

(property property)

(property property value)

Gets, sets or removes (when value is nil) system properties.

Throws when not allowed.

shutdown clj

(shutdown)

(shutdown status)

Terminates the JVM.

Before halting the process, runs shutdown hooks.

Throws when not allowed.

Cf. on-shutdown

timestamp clj

(timestamp)

Current unix time in milliseconds.

Depends on the system time. Not necessarely monotonically increasing.

Only as accurate as the underlying operating system, often measuring time in units of 10's of milliseconds.