fSeek (Function)

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Current position

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fSeek (Function)

In french: fPositionne

Gets and sets current position in an external file.

When opening a file, the current position corresponds to:

the first file byte,
the last file byte if the file is opened in "addition" mode (foAdd constant).

Using the read functions (fRead, fReadLine) and the write functions (fWrite, fWriteLine) modifies the current position.

Example

See additional examples

// Open an external file
FileID is int
ResPosition is int
FileID = fOpen("C:\MyDirectories\File.txt", foReadWrite)
IF FileID <> -1 THEN
...
// Get the current position
ResPosition = fSeek(FileID, 0, fpCurrent)
...
END

// Open an external file
MyTextFile is DiskFile
ResPosition is int
MyTextFile = fOpen("C:\MyDirectories\File.txt", foReadWrite)
IF NOT ErrorOccurred THEN
...
// Get the current position
ResPosition = fSeek(MyFile, 0, fpCurrent)
...
END

Syntax

<Result> = fSeek(<File used> , <Move> , <Source position>)

<Result>: Integer

Current position after modification,
-1 if an error occurred. To get more details on the error, use ErrorInfo with the errMessage constant.
This parameter must be a variant.

<File used>: Integer or DiskFile variable

Identifier of the file to use, defined by fOpen or fCreate.
Name of the DiskFile variable initialized with fOpen or fCreate.
Not available.

<Move>: Integer

Amount of bytes (characters) to offset in the file. To move backwards from the end of the file (fpEnd constant), this number must be negative.

<Source position>: Constant

Specifies the source position:
fpBeginning The source position corresponds to the first file byte (position 0).
fpCurrent The source position corresponds to the current position.
fpEnd The source position corresponds to the last file byte.

Remarks

Handling errors

fSeek throws an error in the following cases:

the file is not opened,
the file is locked by another computer or by another application.

Current position

To retrieve the current position in the external file, use the following syntax:

CurrentPosition = fSeek(FileID, 0, fpCurrent)

No move is performed in the specified file.

Business / UI classification: Business Logic

Component: wd300std.dll