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= Description
The io-extra library provides a few extra IO methods that you may find
handy. They are IO.closefrom, IO.fdwalk, IO.pread, IO.pread_ptr, IO.pwrite,
IO.writev, IO#directio? and IO#directio=.
This library is not supported on MS Windows.
Support for OS X is limited. See below for details.
= Installation
gem install io-extra
= Synopsis
require 'io/extra'
# Close all file descriptors from 3 up.
# Inspect all the open handles
IO.fdwalk(0){ |handle|
puts "=" * 40
p handle
p handle.fileno
# Write an array to an IO object efficiently
IO.writev(fh.fileno, %w[a b c])
= Developer's Notes
You might be wondering what the difference is between my implementation of
IO.closefrom and a pure Ruby version that looks something like this:
def IO.closefrom(n)
0.upto(n) do |fd|
The primary difference is that this walks all file descriptors, rather
than only open file descriptors. However, I should note that this only
applies if your platform supports the closefrom() function. In that case,
the only advantage is speed.
You might also be wondering what the difference is between my implementation
of IO.fdwalk and a pure Ruby version that looks something like this:
def IO.fdwalk(n)
ObjectSpace.each_object(File){ |f|
yield f if f.fileno >= n
The primary difference is that this only closes Ruby file objects, not
necessarily every file handle opened by the Ruby process. For example, handles
opened via system() calls.
= Note to OS X Users
The OS X platform does not support closefrom() or fdwalk(). The hand-
crafted IO.closefrom function will not work because the getrlimit()
function on OS X does not work. Patches welcome.
= Documentation
For further documentation, see the io_extra.txt file or the inline
documentation that was generated by RDoc (if you did a gem install).
= Known Issues
The IO.writev tests fail on Solaris. Short test scripts seem to work,
however. We're not sure what the issue is yet. Help wanted.
Please file any bug reports on the project page at
= Future Plans
* Switch from C extension to FFI.
= Acknowledgements
Eric Wong for some great work on Linux compatibility and other fixes, as
well as the code for the IO.writev method.
= License
Artistic 2.0
= Copyright
(C) 2003-2013 Daniel J. Berger
All Rights Reserved
= Warranty
This package is provided "as is" and without any express or
implied warranties, including, without limitation, the implied
warranties of merchantability and fitness for a particular purpose.
= Author
Daniel J. Berger
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