IO.read ignores valid open_args on Windows
On Microsoft Windows the fopen function accepts many more modes than the standard function:
However, Ruby 1.9 doesn't appear to allow them:
Try to force a sequential scan with 'S', for example¶
IO.read(file, open_args: ['rbS']) # => invalid access mode rbS (ArgumentError)
It looks like checks are being made manually in file.c and if they don't match the predetermined flags then an error is raised. I would submit that the flags should be allowed to be passed through, and fopen should fail on its own if they're invalid.