module FFI::Library

def attach_function(name, func, args, returns = nil, options = nil)

Raises:
  • (FFI::NotFoundError) - if +func+ cannot be found in the attached libraries (see {#ffi_lib})

Returns:
  • (FFI::VariadicInvoker) -

Options Hash: (**options)
  • :type_map (Hash) --
  • :enums (FFI::Enums) --
  • :convention (Symbol) -- calling convention (see {#ffi_convention})
  • :blocking (Boolean) -- set to true if the C function is a blocking call

Parameters:
  • returns (Symbol) -- type of return value
  • args (Array) -- an array of types
  • func (#to_s) -- name of C function to attach
  • name (#to_s) -- name of ruby method to attach as

Other tags:
    Example: attach function with an explicit name -
    Example: attach function without an explicit name -

Overloads:
  • attach_function(name, func, args, returns, options = {})
  • attach_function(func, args, returns, options = {}) 
def attach_function(name, func, args, returns = nil, options = nil)
  mname, a2, a3, a4, a5 = name, func, args, returns, options
  cname, arg_types, ret_type, opts = (a4 && (a2.is_a?(String) || a2.is_a?(Symbol))) ? [ a2, a3, a4, a5 ] : [ mname.to_s, a2, a3, a4 ]
  # Convert :foo to the native type
  arg_types = arg_types.map { |e| find_type(e) }
  options = {
    :convention => ffi_convention,
    :type_map => defined?(@ffi_typedefs) ? @ffi_typedefs : nil,
    :blocking => defined?(@blocking) && @blocking,
    :enums => defined?(@ffi_enums) ? @ffi_enums : nil,
  }
  @blocking = false
  options.merge!(opts) if opts && opts.is_a?(Hash)
  # Try to locate the function in any of the libraries
  invokers = []
  ffi_libraries.each do |lib|
    if invokers.empty?
      begin
        function = nil
        function_names(cname, arg_types).find do |fname|
          function = lib.find_function(fname)
        end
        raise LoadError unless function
        invokers << if arg_types[-1] == FFI::NativeType::VARARGS
          VariadicInvoker.new(function, arg_types, find_type(ret_type), options)
        else
          Function.new(find_type(ret_type), arg_types, function, options)
        end
      rescue LoadError
      end
    end
  end
  invoker = invokers.compact.shift
  raise FFI::NotFoundError.new(cname.to_s, ffi_libraries.map { |lib| lib.name }) unless invoker
  invoker.attach(self, mname.to_s)
  invoker
end