ThreadGroup
provides a means of keeping track of a number of threads as a group.
A given Thread
object can only belong to one ThreadGroup
at a time; adding a thread to a new group will remove it from any previous group.
Newly created threads belong to the same group as the thread from which they were created.
Raised when an invalid operation is attempted on a thread.
For example, when no other thread has been started:
Thread.stop
This will raises the following exception:
ThreadError: stopping only thread note: use sleep to stop forever
Threads are the Ruby implementation for a concurrent programming model.
Programs that require multiple threads of execution are a perfect candidate for Ruby’s Thread
class.
For example, we can create a new thread separate from the main thread’s execution using ::new
.
thr = Thread.new { puts "What's the big deal" }
Then we are able to pause the execution of the main thread and allow our new thread to finish, using join
:
thr.join #=> "What's the big deal"
If we don’t call thr.join
before the main thread terminates, then all other threads including thr
will be killed.
Alternatively, you can use an array for handling multiple threads at once, like in the following example:
threads = [] threads << Thread.new { puts "What's the big deal" } threads << Thread.new { 3.times { puts "Threads are fun!" } }
After creating a few threads we wait for them all to finish consecutively.
threads.each { |thr| thr.join }
To retrieve the last value of a thread, use value
thr = Thread.new { sleep 1; "Useful value" } thr.value #=> "Useful value"
Thread
initialization In order to create new threads, Ruby provides ::new
, ::start
, and ::fork
. A block must be provided with each of these methods, otherwise a ThreadError
will be raised.
When subclassing the Thread
class, the initialize
method of your subclass will be ignored by ::start
and ::fork
. Otherwise, be sure to call super in your initialize
method.
Thread
termination For terminating threads, Ruby provides a variety of ways to do this.
The class method ::kill
, is meant to exit a given thread:
thr = Thread.new { sleep } Thread.kill(thr) # sends exit() to thr
Alternatively, you can use the instance method exit
, or any of its aliases kill
or terminate
.
thr.exit
Thread
status Ruby provides a few instance methods for querying the state of a given thread. To get a string with the current thread’s state use status
thr = Thread.new { sleep } thr.status # => "sleep" thr.exit thr.status # => false
You can also use alive?
to tell if the thread is running or sleeping, and stop?
if the thread is dead or sleeping.
Thread
variables and scope Since threads are created with blocks, the same rules apply to other Ruby blocks for variable scope. Any local variables created within this block are accessible to only this thread.
Each fiber has its own bucket for Thread#[]
storage. When you set a new fiber-local it is only accessible within this Fiber
. To illustrate:
Thread.new { Thread.current[:foo] = "bar" Fiber.new { p Thread.current[:foo] # => nil }.resume }.join
This example uses []
for getting and []=
for setting fiber-locals, you can also use keys
to list the fiber-locals for a given thread and key?
to check if a fiber-local exists.
When it comes to thread-locals, they are accessible within the entire scope of the thread. Given the following example:
Thread.new{ Thread.current.thread_variable_set(:foo, 1) p Thread.current.thread_variable_get(:foo) # => 1 Fiber.new{ Thread.current.thread_variable_set(:foo, 2) p Thread.current.thread_variable_get(:foo) # => 2 }.resume p Thread.current.thread_variable_get(:foo) # => 2 }.join
You can see that the thread-local :foo
carried over into the fiber and was changed to 2
by the end of the thread.
This example makes use of thread_variable_set
to create new thread-locals, and thread_variable_get
to reference them.
There is also thread_variables
to list all thread-locals, and thread_variable?
to check if a given thread-local exists.
Exception
handling When an unhandled exception is raised inside a thread, it will terminate. By default, this exception will not propagate to other threads. The exception is stored and when another thread calls value
or join
, the exception will be re-raised in that thread.
t = Thread.new{ raise 'something went wrong' } t.value #=> RuntimeError: something went wrong
An exception can be raised from outside the thread using the Thread#raise
instance method, which takes the same parameters as Kernel#raise
.
Setting Thread.abort_on_exception
= true, Thread#abort_on_exception
= true, or $DEBUG = true will cause a subsequent unhandled exception raised in a thread to be automatically re-raised in the main thread.
With the addition of the class method ::handle_interrupt
, you can now handle exceptions asynchronously with threads.
Ruby provides a few ways to support scheduling threads in your program.
The first way is by using the class method ::stop
, to put the current running thread to sleep and schedule the execution of another thread.
Once a thread is asleep, you can use the instance method wakeup
to mark your thread as eligible for scheduling.
You can also try ::pass
, which attempts to pass execution to another thread but is dependent on the OS whether a running thread will switch or not. The same goes for priority
, which lets you hint to the thread scheduler which threads you want to take precedence when passing execution. This method is also dependent on the OS and may be ignored on some platforms.
Solves a*x = b for x, using LU decomposition.
The Readline
module provides interface for GNU Readline
. This module defines a number of methods to facilitate completion and accesses input history from the Ruby interpreter. This module supported Edit Line(libedit) too. libedit is compatible with GNU Readline
.
Reads one inputted line with line edit by Readline.readline
method. At this time, the facilitatation completion and the key bind like Emacs can be operated like GNU Readline
.
require "readline" while buf = Readline.readline("> ", true) p buf end
The content that the user input can be recorded to the history. The history can be accessed by Readline::HISTORY
constant.
require "readline" while buf = Readline.readline("> ", true) p Readline::HISTORY.to_a print("-> ", buf, "\n") end
Documented by Kouji Takao <kouji dot takao at gmail dot com>.
Calculates the set of unambiguous abbreviations for a given set of strings.
require 'abbrev' require 'pp' pp Abbrev.abbrev(['ruby']) #=> {"ruby"=>"ruby", "rub"=>"ruby", "ru"=>"ruby", "r"=>"ruby"} pp Abbrev.abbrev(%w{ ruby rules })
Generates:
{ "ruby" => "ruby", "rub" => "ruby", "rules" => "rules", "rule" => "rules", "rul" => "rules" }
It also provides an array core extension, Array#abbrev
.
pp %w{ summer winter }.abbrev
Generates:
{ "summer" => "summer", "summe" => "summer", "summ" => "summer", "sum" => "summer", "su" => "summer", "s" => "summer", "winter" => "winter", "winte" => "winter", "wint" => "winter", "win" => "winter", "wi" => "winter", "w" => "winter" }
mkmf.rb is used by Ruby C extensions to generate a Makefile which will correctly compile and link the C extension to Ruby and a third-party library.
RubyGems is the Ruby standard for publishing and managing third party libraries.
For user documentation, see:
gem help
and gem help [command]
For gem developer documentation see:
Gem::Version
for version dependency notes
Further RubyGems documentation can be found at:
RubyGems API (also available from gem server
)
RubyGems will load plugins in the latest version of each installed gem or $LOAD_PATH. Plugins must be named ‘rubygems_plugin’ (.rb, .so, etc) and placed at the root of your gem’s require_path. Plugins are installed at a special location and loaded on boot.
For an example plugin, see the Graph gem which adds a gem graph
command.
RubyGems defaults are stored in lib/rubygems/defaults.rb. If you’re packaging RubyGems or implementing Ruby you can change RubyGems’ defaults.
For RubyGems packagers, provide lib/rubygems/defaults/operating_system.rb and override any defaults from lib/rubygems/defaults.rb.
For Ruby implementers, provide lib/rubygems/defaults/#{RUBY_ENGINE}.rb and override any defaults from lib/rubygems/defaults.rb.
If you need RubyGems to perform extra work on install or uninstall, your defaults override file can set pre/post install and uninstall hooks. See Gem::pre_install
, Gem::pre_uninstall
, Gem::post_install
, Gem::post_uninstall
.
You can submit bugs to the RubyGems bug tracker on GitHub
RubyGems is currently maintained by Eric Hodel.
RubyGems was originally developed at RubyConf 2003 by:
Rich Kilmer – rich(at)infoether.com
Chad Fowler – chad(at)chadfowler.com
David Black – dblack(at)wobblini.net
Paul Brannan – paul(at)atdesk.com
Jim Weirich – jim(at)weirichhouse.org
Contributors:
Gavin Sinclair – gsinclair(at)soyabean.com.au
George Marrows – george.marrows(at)ntlworld.com
Dick Davies – rasputnik(at)hellooperator.net
Mauricio Fernandez – batsman.geo(at)yahoo.com
Simon Strandgaard – neoneye(at)adslhome.dk
Dave Glasser – glasser(at)mit.edu
Paul Duncan – pabs(at)pablotron.org
Ville Aine – vaine(at)cs.helsinki.fi
Eric Hodel – drbrain(at)segment7.net
Daniel Berger – djberg96(at)gmail.com
Phil Hagelberg – technomancy(at)gmail.com
Ryan Davis – ryand-ruby(at)zenspider.com
Evan Phoenix – evan(at)fallingsnow.net
Steve Klabnik – steve(at)steveklabnik.com
(If your name is missing, PLEASE let us know!)
See LICENSE.txt for permissions.
Thanks!
-The RubyGems Team
This library is an interface to secure random number generators which are suitable for generating session keys in HTTP cookies, etc.
You can use this library in your application by requiring it:
require 'securerandom'
It supports the following secure random number generators:
openssl
/dev/urandom
SecureRandom
is extended by the Random::Formatter
module which defines the following methods:
alphanumeric
base64
choose
hex
rand
random_bytes
random_number
urlsafe_base64
uuid
These methods are usable as class methods of SecureRandom
such as SecureRandom.hex
.
If a secure random number generator is not available, NotImplementedError
is raised.
exception to wait for reading by EINPROGRESS. see IO.select
.
Parent class for server error (5xx) HTTP
response classes.
A server error response indicates that the server failed to fulfill a request.
References:
Response class for Already Reported (WebDAV)
responses (status code 208).
The Already Reported (WebDAV)
response indicates that the server has received the request, and that the members of a DAV binding have already been enumerated in a preceding part of the (multi-status) response, and are not being included again. See 208 Already Reported (WebDAV).
Response class for Permanent Redirect
responses (status code 308).
This and all future requests should be directed to the given URI
. See 308 Permanent Redirect.
Response class for Payment Required
responses (status code 402).
Reserved for future use. See 402 Payment Required.
Response class for Length Required
responses (status code 411).
The request did not specify the length of its content, which is required by the requested resource. See 411 Length Required.
Response class for Upgrade Required
responses (status code 426).
The client should switch to the protocol given in the Upgrade header field. See 426 Upgrade Required.
Response class for Internal Server Error
responses (status code 500).
An unexpected condition was encountered and no more specific message is suitable. See 500 Internal Server Error.
Raised on redirection, only occurs when redirect
option for HTTP is false
.
Indicates a failure to resolve a name or address.
This Gem::StreamUI
subclass records input and output to StringIO
for retrieval during tests.
Given a set of Gem::Dependency
objects as needed
and a way to query the set of available specs via set
, calculates a set of ActivationRequest
objects which indicate all the specs that should be activated to meet the all the requirements.
Raised by Encoding
and String
methods when the source encoding is incompatible with the target encoding.