What timeout values are accepted for poll()

If timeout is greater than zero, it specifies a maximum interval (in milliseconds) to wait for any file descriptor to become ready. If timeout is zero, then poll() will return without blocking. If the value of timeout is -1, the poll blocks indefinitely.

as of Mac OS X 10.5;

Maximum interval to wait for the poll to complete, in milliseconds. If this value is 0, poll() will return immediately. If this value is INFTIM (-1), poll() will block indefinitely until a condition is found.