Syntax:

Lock (resource, timeout)

Parameters:

resource – Any expression that returns an Alpha string. Its maximum length is 128.

timeout – the maximum wait time in seconds. A negative value equals an infinite wait.

Returns:

Number to indicate if lock was successful:

0 = Lock was successful.

1 = Resource is already locked by same session.

2 = Resource is locked by another user and the timeout has expired.

Note:

• A zero length string is a valid name. In case of a recursive lock, the user must issue an UnLock command for each Lock command to fully unlock the resource.

• The function polls every 500 milliseconds.