popen bufsize not allowed on windows

[Jonathan Hudgins]

When I try setting the bufsize on popen on windows I get the following error:

    output = os.popen( "ls", 'r', 1 )

ValueError: popen() arg 3 must be -1

The same is true for popen2, popen3 and popen4.

Is this a known limitation?  Intentional?
Are there plans to fix this?  (Or at least the documentation)

Jonathan