Issue #5138 has been updated by tenderlovemaking (Aaron Patterson).

File feature5138.pdf added

New slide.
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Feature #5138: Add nonblocking IO that does not use exceptions for EOF and EWOULDBLOCK
https://bugs.ruby-lang.org/issues/5138#change-27612

Author: wycats (Yehuda Katz)
Status: Assigned
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: 1.9.4


The current Ruby I/O classes have non-blocking methods (read_nonblock and write_nonblock). These methods will never block, and if they would block, they raise an exception instead (IO::WaitReadable or IO::WaitWritable). In addition, if the IO is at EOF, they raise an EOFError.

These exceptions are raised repeatedly in virtually every use of the non-blocking methods. This patch adds a pair of methods (try_read_nonblock and try_write_nonblock) that have the same semantics as the existing methods, but they return Symbols instead of raising exceptions for these routine cases:

* :read_would_block
* :write_would_block
* :eof

The patch contains updates for IO, StringIO, and OpenSSL. The updates are fully documented and tested.


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