filesystem/file_for_descriptor.rb

tests/_examples/filesystem/file_for_descriptor.rb in the metorex repository.

# File.for_fd with no mode uses the descriptor the way it was opened.
path = "/tmp/metorex_file_for_descriptor_#{Process.pid}.txt"
opened = File.open(path, "w+")
adopted = File.for_fd(opened.fileno)
adopted.autoclose = false
p(adopted.write("written through the descriptor"))
adopted.close
opened.close
p(File.read(path))
File.delete(path)

Output:

30
"written through the descriptor"