Name
Reset Procedure
Syntax
procedure Reset(var F: TextFile); procedure Reset(var F: File); procedure Reset(var F: File; RecordSize: Integer);
Description
The Reset
procedure opens an existing file. If the
file is a TextFile
, Reset
opens
the file for read-only access. If the file is a binary file, the file
is opened to allow read and write function calls, but the
FileMode
variable dictates how the operating
system opens the file. Reset
is not a real
procedure.
If the file is a typed binary file (e.g., file
of
something
), use the
second form of Reset
, that is, pass the file
variable only. If the file is an untyped binary file (just
file
), you can optionally supply the second
argument to tell Delphi the record size. If you omit the record size,
Delphi uses 128
bytes.
Errors
Reset
reports I/O error 102 if you fail to callAssignFile
prior to callingReset
.If
Reset
cannot open the file, it reports the Windows error code as an I/O error.
Tips and Tricks
If the file is already open, it is closed first.
By default,
Reset
opens a binary file to allow reading and writing. Set theFileMode
variable to before callingReset
to open a file for read-only access.To use
Reset
to append to a binary file, open the file, seek to the end of the file, and then begin writing.When using an untyped file, it is usually simplest to supply a record size of 1 when calling
Reset
, and then callBlockRead
andBlockWrite
to read and write as much data as you want. Alternatively, create a type forFile
of
Byte
, so ...
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