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Categories / Delphi / Procedures
 

Reset - open a text file for reading, or binary file for read-write system unit

1 procedure Reset ( var FileHandle : TextFile ) ; 2 procedure Reset ( var FileHandle : File {RecordSize ) ; Description The Reset procedure opens a file given by FileHandle for read, write or read and write access. You must use AssignFile to assign a file to the FileHandle before using Reset. Use Write or WriteLn to write to the file after this Reset is executed. Version 1 Is used for text files. They can only be read after opening with Reset. Version 2 Is for binary files. Before using Reset, you must set FileMode to one of the following: fmOpenRead : Read only fmOpenWrite : Write only fmOpenReadWrite : Read and write The optional RecordSize value is used to override the default 128 byte record size for binary (untyped) files. For such files, only BlockRead and BlockWrite can be used. Related commands Append Open a text file to allow appending of text to the end AssignFile Assigns a file handle to a binary or text file CloseFile Closes an open file File Defines a typed or untyped file ReWrite Open a text or binary file for write access TextFile Declares a file type for storing lines of text Example code : Writing and reading lines of text to/from a text file var myFile : TextFile; text : string; begin // Try to open the Test.txt file for writing to AssignFile(myFile, 'Test.txt'); ReWrite(myFile); // Write a couple of well known words to this file WriteLn(myFile, 'Hello'); WriteLn(myFile, 'World'); // Close the file CloseFile(myFile); // Reopen the file in read only mode FileMode := fmOpenRead; Reset(myFile); // Display the file contents while not Eof(myFile) do begin ReadLn(myFile, text); ShowMessage(text); end; // Close the file for the last time CloseFile(myFile); end; Show full unit code Hello World