Hi,

In message "[RCR] #59 Add fsync method to IO class"
    on 02/01/17, Leslie Hensley <hensleyl / papermountain.org> writes:

|Adding fsync and fdatasync methods to the IO class will allow Ruby to
|be used to address problem domains where it must be guaranteed that
|data has been written to the disk. Examples of these are logging for
|security purposes and transactional systems. The posix functions fsync
|and fdatasync guarantee that any data that the OS is buffering for a
|file is written to disk. This is distinct from IO#sync= which only
|addresses if Ruby buffers the data above the OS level. As for
|portability concerns, these methods seem just as reasonable as
|IO#fcntl.

My concerns are:

  * how common are they?
  * what if it's not defined on the platform?

							matz.