Obtains a logical lock on a variable name.

Lock(varname[, timeout])

The Lock function has the following parameters:

Returns true if the lock was obtained, false otherwise.

Each time a lock is obtained on a varname a lock count is incremented for this varname. Unlock decrements this count. Only when the lock count falls to zero will the logical lock be released. For this reason, you should balance each call to Lock with a corresponding call to Unlock.

The following example uses the Lock function to obtain a logical lock on a varname with a timeout of 10 seconds.

If Lock(^PatientData(PatientID), 10) = True Then
	Println "Got the Lock"
	Unlock(^PatientData(PatientID))
Else
	Println "Couldn't get the lock"
End If

If a timeout is not specified, Lock will wait indefinitely for the lock to be obtained. Specifying a timeout causes the lock attempt to wait up to the timeout number of seconds to obtain the lock.