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LOF Function

Visual Studio 2008

Returns a Long representing the size, in bytes, of a file opened using the FileOpen function.

The My feature gives you greater productivity and performance in file I/O operations than LOF. For more information, see My.Computer.FileSystem Object.

Public Function LOF(ByVal FileNumber As Integer) As Long


Required. An Integer containing a valid file number.

Exception type

Error number




FileNumber does not exist.



File mode is invalid.

See the "Error number" column if you are upgrading Visual Basic 6.0 applications that use unstructured error handling. (You can compare the error number against the Number Property (Err Object).) However, when possible, you should consider replacing such error control with Structured Exception Handling Overview for Visual Basic.

Use the FileLen function to obtain the length of a file that is not open.

This example uses the LOF function to determine the size of an open file. This example assumes that TestFile is a text file containing sample data.

Dim length As Long
FileOpen(1, "C:\TESTFILE.TXT", OpenMode.Input) ' Open file.
length = LOF(1)   ' Get length of file.
FileClose(1)   ' Close file.

This function is not supported.

Namespace: Microsoft.VisualBasic

Module: FileSystem

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)