Tallies the collection, i.e., counts the occurrences of each element. Returns a hash with the elements of the collection as keys and the corresponding counts as values.
["a", "b", "c", "b"].tally #=> {"a"=>1, "b"=>2, "c"=>1}
SystemCallError
is the base class for all low-level platform-dependent errors.
The errors available on the current platform are subclasses of SystemCallError
and are defined in the Errno
module.
File.open("does/not/exist")
raises the exception:
Errno::ENOENT: No such file or directory - does/not/exist
Helper methods for both Gem::Installer
and Gem::Uninstaller
Installs a gem along with all its dependencies from local and remote gems.
Raised when removing a gem with the uninstall command fails
The installer installs the files contained in the .gem into the Gem.home.
Gem::Installer
does the work of putting files in all the right places on the filesystem including unpacking the gem into its gem dir, installing the gemspec in the specifications dir, storing the cached gem in the cache dir, and installing either wrappers or symlinks for executables.
The installer invokes pre and post install hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_install
and Gem.post_install
for details.
An Uninstaller
.
The uninstaller fires pre and post uninstall hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#{RUBY_ENGINE}.rb or rubygems/defaults/operating_system.rb file. See Gem.pre_uninstall
and Gem.post_uninstall
for details.
Mixin methods for install and update options for Gem::Commands
Socket::AncillaryData
represents the ancillary data (control information) used by sendmsg and recvmsg system call. It contains socket family
, control message (cmsg) level
, cmsg type
and cmsg data
.
Represents a fatal SMTP
error (error code 5xx, except for 500)
Raised when a signal is received.
begin Process.kill('HUP',Process.pid) sleep # wait for receiver to handle signal sent by Process.kill rescue SignalException => e puts "received Exception #{e}" end
produces:
received Exception SIGHUP
The most standard error types are subclasses of StandardError
. A rescue clause without an explicit Exception
class will rescue all StandardErrors (and only those).
def foo raise "Oups" end foo rescue "Hello" #=> "Hello"
On the other hand:
require 'does/not/exist' rescue "Hi"
raises the exception:
LoadError: no such file to load -- does/not/exist