Read in a number of characters from a previously opened file.
FileRead ( "filehandle/filename" [, count] )
| filehandle/filename | The handle of a file, as returned by a previous call to FileOpen(). Alternatively you may use a string filename as the first parameter. |
| count | [optional] The number of characters to read. See remarks. |
| Success: | the binary/string read. @extended is set to the number of bytes/characters returned. |
| Failure: | sets the @error flag to non-zero. |
| @error: | 1 = if file not opened in read mode or other error -1 = if end-of-file is reached |
A negative or not defined count, reads the whole file from the current position.
If a filename is given rather than a file handle - the file will be opened and closed during the function call - for parsing large files this will be much slower than using filehandles.
Note: Do not mix filehandles and filenames, i.e., don't FileOpen() a file and then use a filename in this function. Use either filehandles or filenames in your routines, not both!
Both ANSI and UTF16/UTF8 text formats can be read - See FileOpen() for details.
If the UTF8 conversion to string cannot be performed, ANSI text format is assumed. This can occured on very large number of characters read.
A file can be read as binary (byte) data by using FileOpen() with the binary flag - in this case count is in bytes rather than characters. A count value that is too large can lead to AutoIt stopping with a memory allocation failure.
FileGetPos, FileOpen, FileReadLine, FileSetPos, FileWrite, FileWriteLine, String
#include <FileConstants.au3>
#include <MsgBoxConstants.au3>
#include <WinAPIFiles.au3>
Example()
Func Example()
; Create a constant variable in Local scope of the filepath that will be read/written to.
Local Const $sFilePath = _WinAPI_GetTempFileName(@TempDir)
; Create a temporary file to read data from.
If Not FileWrite($sFilePath, "This is an example of using FileRead.") Then
MsgBox($MB_SYSTEMMODAL, "", "An error occurred whilst writing the temporary file.")
Return False
EndIf
; Open the file for reading and store the handle to a variable.
Local $hFileOpen = FileOpen($sFilePath, $FO_READ)
If $hFileOpen = -1 Then
MsgBox($MB_SYSTEMMODAL, "", "An error occurred when reading the file.")
Return False
EndIf
; Read the contents of the file using the handle returned by FileOpen.
Local $sFileRead = FileRead($hFileOpen)
; Close the handle returned by FileOpen.
FileClose($hFileOpen)
; Display the contents of the file.
MsgBox($MB_SYSTEMMODAL, "", "Contents of the file:" & @CRLF & $sFileRead)
; Delete the temporary file.
FileDelete($sFilePath)
EndFunc ;==>Example