Example: Lock and unlock statements

Type PersonRecord
   empNumber As Integer
   empName As String * 20
End Type
Dim rec1 As PersonRecord, rec2 As PersonRecord
Dim fileNum As Integer, recNum As Integer
Dim fileName As String
recNum% = 1
fileNum% = FreeFile()
fileName$ = "data.txt"
' Create a record.
Open fileName$ For Random As fileNum%
rec1.empNumber% = 123
rec1.empName$ = "John Smith"
Put #fileNum, recNum%, rec1
Print rec1.empName$ ; rec1.empNumber%
' Output:
' John Smith           123
' Lock and update the record.
Lock #fileNum%, recNum%
Get #fileNum%, recNum%, rec2
Print rec2.empName$ ; rec2.empNumber%
' Output:
' John Smith           123
rec2.empName$ = "John Doe"
Put #fileNum%, recNum%, rec2
Print rec2.empName$ ; rec2.empNumber%
' Output:
' John Doe             123
' Release the lock.
Unlock #fileNum%, recNum%
Close fileNum%