Вот че отцы советуют
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Private Const GENERIC_WRITE = &H40000000
Private Const FILE_ATTRIBUTE_NORMAL = &H80
Private Const OPEN_EXISTING = 3
'
Private Const FILE_BEGIN = 0
Private Const FILE_CURRENT = 1
Private Const FILE_END = 2
'
Private Type SECURITY_ATTRIBUTES
nLength As Long
lpSecurityDescriptor As Long
bInheritHandle As Long
End Type
'
Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" ( _
ByVal lpFileName As String, _
ByVal dwDesiredAccess As Long, _
ByVal dwShareMode As Long, _
ByRef lpSecurityAttributes As SECURITY_ATTRIBUTES, _
ByVal dwCreationDisposition As Long, _
ByVal dwFlagsAndAttributes As Long, _
ByVal hTemplateFile As Long) As Long
'
Private Declare Function SetFilePointer Lib "kernel32" ( _
ByVal hFile As Long, _
ByVal lDistanceToMove As Long, _
lpDistanceToMoveHigh As Long, _
ByVal dwMoveMethod As Long) As Long
'
Private Declare Function SetEndOfFile Lib "kernel32" (ByVal hFile As Long) As Long
Удачи......