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# sysvmq [![Build Status](https://travis-ci.org/Sirupsen/sysvmq.png?branch=v0.1.0)](https://travis-ci.org/Sirupsen/sysvmq)

`sysvmq` is a C extension that wraps SysV IPC Message Queues. It's similar to
the [POSIX MQ Ruby wrapper](https://github.com/Sirupsen/posix-mqueue). Message
queues are handy for interprocess communication where you want to be able to
take down either endpoint easily. The main disadvantage of SysV message queues
over POSIX MQs (on Linux) is that SysV doesn't expose a file descriptor to do
e.g. `select(2)` on.

Note that `sysvmq` doesn't rely on any third-party message broker. The message
queue is handled by the kernel. It's extremely stable and performant.

## Installation

Add `sysvm` to your Gemfile.

`gem 'sysvmq'`

Currently known to work on Linux and OS X for MRI >= 2.0.

## Usage

```ruby
# Create a message queue with a 1024 byte buffer.
require 'sysvmq'
mq = SysVMQ.new(0xDEADC0DE, 1024, SysVMQ::IPC_CREAT | 0666)

mq.send "Hellø Wårld!"
assert_equal 1, mq.stats[:count]

assert_equal "Hellø Wårld!", mq.receive

# Raise an exception instead of blocking until a message is available
mq.receive(0, SysVMQ::IPC_NOWAIT)

ensure
# Delete queue
mq.destroy
```

## Todo

* Explain messages types
* Add named params for flags (e.g. `mq.receive(:front, blocking: false)`)
  instead of ORing flags directly.
* Add `IPC_INFO` on Linux
* Add all of `IPC_STAT`

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
sysvmq-0.1.1	README.md