Function Reference


_WinAPI_SetEndOfFile

Sets the physical file size for the specified file to the current position of the file pointer

#include <WinAPI.au3>
_WinAPI_SetEndOfFile ( $hFile )

Parameters

$hFile Handle to the file to be extended or truncated.
The file handle must have the $GENERIC_WRITE access right.

Return Value

Success: True
Failure: False, call _WinAPI_GetLastError() to get extended error information

Remarks

This function can be used to truncate or extend a file.
If the file is extended, the contents of the file between the old end of the file and the new end of the file are not defined.
This function sets the file size.

Related

_WinAPI_CloseHandle, _WinAPI_CreateFile, _WinAPI_FlushFileBuffers, _WinAPI_GetFileSizeEx, _WinAPI_ReadFile, _WinAPI_SetFilePointer, _WinAPI_WriteFile

See Also

Search SetEndOfFile in MSDN Library.

Example

#include <WinAPI.au3>

Local $sTempFile, $hFile, $sText, $nBytes, $tBuffer, $iSize

; 1) create file and write data to it
$sTempFile = @TempDir & '\test.txt'
$sText = 'abcdefghijklmnopqrstuvwxyz'
$tBuffer = DllStructCreate("byte[" & StringLen($sText) & "]")
DllStructSetData($tBuffer, 1, $sText)
$hFile = _WinAPI_CreateFile($sTempFile, 1)
_WinAPI_WriteFile($hFile, $tBuffer, StringLen($sText), $nBytes)
$iSize = _WinAPI_GetFileSizeEx($hFile)
_WinAPI_CloseHandle($hFile)
ConsoleWrite('1):' & $iSize & ' ' & FileRead($sTempFile) & @CRLF)

; 2) read 6 bytes from position 3
$tBuffer = DllStructCreate("byte[6]")
$hFile = _WinAPI_CreateFile($sTempFile, 2, 2)
$iSize = _WinAPI_GetFileSizeEx($hFile)
_WinAPI_SetFilePointer($hFile, 3)
_WinAPI_ReadFile($hFile, $tBuffer, 6, $nBytes)
_WinAPI_CloseHandle($hFile)
$sText = BinaryToString(DllStructGetData($tBuffer, 1))
ConsoleWrite('2):' & $iSize & ' ' & $sText & @CRLF)

; 3) write previously read 6 bytes from position 3 to the same position but in UpperCase
DllStructSetData($tBuffer, 1, StringUpper($sText))
$hFile = _WinAPI_CreateFile($sTempFile, 2, 4)
$iSize = _WinAPI_GetFileSizeEx($hFile)
_WinAPI_SetFilePointer($hFile, 3)
_WinAPI_WriteFile($hFile, $tBuffer, 6, $nBytes)
_WinAPI_CloseHandle($hFile)
$tBuffer = 0
ConsoleWrite('3):' & $iSize & ' ' & FileRead($sTempFile) & @CRLF)

; 4) truncate file size to 12 bytes
$hFile = _WinAPI_CreateFile($sTempFile, 2, 4)
_WinAPI_SetFilePointer($hFile, 12)
_WinAPI_SetEndOfFile($hFile)
$iSize = _WinAPI_GetFileSizeEx($hFile)
_WinAPI_CloseHandle($hFile)
ConsoleWrite('4):' & $iSize & ' ' & FileRead($sTempFile) & @CRLF)

FileDelete($sTempFile)