File Object [AHK_L 42+]

Provides an interface for file input/output. FileOpen returns an object of this type.

Read

Reads a string of characters from the file and advances the file pointer.

String := File.Read([Characters])
CharactersThe maximum number of characters to read. If omitted, the rest of the file is read and returned as one string. If the File object was created from a handle to a non-seeking device such as a console buffer or pipe, omitting this parameter may cause the method to fail or return only what data is currently available.
ReturnsA string.

Write

Writes a string of characters to the file and advances the file pointer.

File.Write(String)
StringA string.
ReturnsThe number of bytes (not characters) that were written.

ReadLine

Reads a line of text from the file and advances the file pointer.

Line := File.ReadLine()
ReturnsA line of text. This may include `n, `r`n or `r depending on the file and EOL flags used to open the file.

Lines up to 65,534 characters long can be read. If the length of a line exceeds this, the remainder of the line is returned by subsequent calls to this method.

WriteLine

Writes a string of characters followed by `n or `r`n depending on the flags used to open the file. Advances the file pointer.

File.WriteLine([String])
StringAn optional string.
ReturnsThe number of bytes (not characters) that were written.

ReadNum

Reads a number from the file and advances the file pointer.

Num := File.ReadNumType()
NumType One of the following specified directly as part of the function name:
UInt, Int, Int64, Short, UShort, Char, UChar, Double, or Float.

These type names have the same meanings as with DllCall.

ReturnsA number if successful, otherwise an empty string.

If a Try statement is active and no bytes were read, an exception is thrown. However, no exception is thrown if at least one byte was read, even if the size of the given NumType is greater than the number of bytes read. Instead, the missing bytes are assumed to be zero.

WriteNum

Writes a number to the file and advances the file pointer.

File.WriteNumType(Num)
NumType One of the following specified directly as part of the function name:
UInt, Int, Int64, Short, UShort, Char, UChar, Double, or Float.

These type names have the same meanings as with DllCall.

NumA number.
ReturnsThe number of bytes that were written. For instance, WriteUInt returns 4 if successful.

RawRead

Read raw binary data from the file into memory. If a var is specified, it is expanded automatically when necessary.

File.RawRead(VarOrAddress, Bytes)
VarOrAddressA variable or memory address to which the data will be copied. Usage is similar to NumGet.
BytesThe maximum number of bytes to read.
ReturnsThe number of bytes that were read.

If a Try statement is active and Bytes is non-zero but no bytes were read, an exception is thrown. AtEOF can be used to avoid this, if needed.

RawWrite

Write raw binary data to the file.

File.RawWrite(VarOrAddress, Bytes)
VarOrAddressA variable containing the data or the address of the data in memory. Usage is similar to NumPut.
BytesThe number of bytes to write.
ReturnsThe number of bytes that were written.

Seek

Moves the file pointer.

File.Seek(Distance [, Origin = 0])
File.Position := Distance
File.Pos := Distance
DistanceDistance to move, in bytes. Lower values are closer to the beginning of the file.
OriginStarting point for the file pointer move. Must be one of the following:
  • 0 (SEEK_SET): Beginning of the file. Distance must be zero or greater.
  • 1 (SEEK_CUR): Current position of the file pointer.
  • 2 (SEEK_END): End of the file. Distance should usually be negative.
If omitted, Origin defaults to SEEK_END when Distance is negative and SEEK_SET otherwise.
ReturnsA non-zero value if successful, otherwise zero.

Tell

Pos := File.Tell()
Pos := File.Position
Pos := File.Pos
ReturnsThe current position of the file pointer, where 0 is the beginning of the file.

Length

Retrieves or sets the size of the file.

FileSize := File.Length
File.Length := NewSize
NewSizeThe new size of the file, in bytes.
ReturnsThe size of the file, in bytes.

This property should be used only with an actual file. If the File object was created from a handle to a pipe, it may return the amount of data currently available in the pipe's internal buffer, but this behaviour is not guaranteed.

AtEOF

IsAtEOF := File.AtEOF
ReturnsA non-zero value if the file pointer has reached the end of the file, otherwise zero.

This property should be used only with an actual file. If the File object was created from a handle to a non-seeking device such as a console buffer or pipe, the returned value may not be meaningful, as such devices do not logically have an "end of file".

Close

Closes the file, flushes any data in the cache to disk and releases the share locks. Although the file is closed automatically when the object is freed, it is recommended to close the file as soon as possible.

File.Close()

No parameters or return value.

Encoding

Retrieves or sets the text encoding used by this file object.

Encoding := File.Encoding
File.Encoding := Encoding
EncodingA numeric code page identifier (see MSDN) or one of the following strings:
  • UTF-8: Unicode UTF-8, equivalent to CP65001.
  • UTF-16: Unicode UTF-16 with little endian byte order, equivalent to CP1200.
  • CPnnn: a code page with numeric identifier nnn.

Encoding never returns a value with the -RAW suffix, regardless of how the file was opened or whether it contains a byte order mark (BOM). Setting Encoding never causes a BOM to be added or removed, as the BOM is normally written to the file when it is first created.

Setting Encoding to UTF-8-RAW or UTF-16-RAW is valid in v1.1.15.04+, but the -RAW suffix is ignored. In earlier versions, UTF-8-RAW and UTF-16-RAW behaved like an invalid 8-bit encoding, causing all non-ASCII characters to be discarded. This only applies to File.Encoding, not FileOpen().

__Handle

File.__Handle
ReturnsA system file handle, intended for use with DllCall. See CreateFile.

File objects internally buffer reads or writes. If data has been written into the object's internal buffer, it is committed to disk before the handle is returned. If the buffer contains data read from file, it is discarded and the actual file pointer is reset to the logical position indicated by File.Pos.