Issue #4538 has been reported by Eric Wong.

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Feature #4538: [PATCH (cleanup)] avoid unnecessary select() calls before doing I/O
http://redmine.ruby-lang.org/issues/4538

Author: Eric Wong
Status: Open
Priority: Low
Assignee: 
Category: core
Target version: 1.9.x


Please look at http://redmine.ruby-lang.org/issues/4535 before
this one.  That one actually fixes a bug I noticed while working
on this patch.

Ruby 1.9 no longer depends on multiplexed non-blocking I/O
to do its threading and defaults to blocking file descriptors.

As a result, there is no need to check the fd for read/writability when
there is an error check for rb_io_wait_(read|writ)able after the
blocking function.

I also believe the code in io_binwrite() to:
    avoid context switch between "a" and "\n" in STDERR.puts "a".
    [ruby-dev:25080]
...has always been broken under 1.9 with native threads.

Nothing new is broken with test-all and test-rubyspec



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