Ruby exception objects are subclasses of Exception. However,
operating systems typically report errors using plain
integers. Module Errno is created dynamically to map these
operating system errors to Ruby classes, with each error number generating
its own subclass of SystemCallError. As the subclass is created
in module Errno, its name will start Errno::.
The names of the Errno:: classes depend on the environment in
which Ruby runs. On a typical Unix or Windows platform, there are
Errno classes such as Errno::EACCES,
Errno::EAGAIN, Errno::EINTR, and so on.
The integer operating system error number corresponding to a
particular error is available as the class constant
Errno::error::Errno.
Errno::EACCES::Errno
»
13
Errno::EAGAIN::Errno
»
11
Errno::EINTR::Errno
»
4
The full list of operating system errors on your particular
platform are available as the constants of Errno.
