crystal-posix/ioctl.cr

libc's ioctl for crystal

ioctl.cr

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libc's ioctl for Crystal.

Features

• Maps in the libc ioctl function.

• Provides C equivalent methods for defining and working with ioctl numbers:

  C	Crystal
  _IOC	IOCTL._IOC(dir,type,nr,size)
  _IO	IOCTL._IO(type,nr)
  _IOR	IOCTL._IOR(type,nr,size)
  _IOW	IOCTL._IOW(type,nr,size)
  _IOWR	IOCTL._IOWR(type,nr,size)
  _IOC_DIR	IOCTL._IOC_DIR(dir)
  _IOC_TYPE	IOCTL._IOC_TYPE(type)
  _IOC_NR	IOCTL._IOC_NR(nr)
  _IOC_SIZE	IOCTL._IOC_SIZE(size)

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     ioctl:
       github: postmodern/ioctl.cr

2. Run shards install

Usage

require "ioctl"

output = MyStruct.new

begin
  IOCTL.ioctl(fd, IOCTL::..., pointerof(output))
request error : IOCTL::Error
  # ...
end

Returning -1 instead of raising an exception:

if LibC.ioctl(fd, IOCTL::..., pointerof(output)) == -1
  # ...
end

Examples

Get the terminal window size:

winsize = LibC::Winsize.new

begin
  IOCTL.ioctl(STDOUT.fd, IOCTL::TIOCGWINSZ, pointerof(winsize))
rescue error : IOCTL::Error
  STDERR.puts error.message
  exit -1
end

puts "Rows: #{winsize.ws_row}"
puts "Cols: #{winsize.ws_col}"

TODO

• macOS / BSD support

Contributing

1. Fork it (https://github.com/postmodern/ioctl/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Postmodern - creator and maintainer

ioctl.cr's Issues

Could this be in the stdlib

Seems like this could be something in the stdlib. Have you thought about trying to get this in the Crystal Compiler?