Mega Code Archive
Filepos - gives the file position in a binary or text file system unit
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1 function FilePos ( var FileHandle : File; ) : LongInt;
2 function FilePos ( car FileHandle : TextFile; ) ;
Description
The FilePos function returns the current position in an open file. The returned value is the Record position, starting at 0 for the file beginning.
The file may be an Untyped, Typed or Text file.
The record length is as follows:
Untyped files : As set in Reset or ReWrite
Typed files : SizeOf the file type
Text files : Variable - defined by line ends
Notes
Seek to the given record position only works for binary files.
Related commands
Eoln Returns true if the current text file is pointing at a line end
File Defines a typed or untyped file
Seek Move the pointer in a binary file to a new record position
SeekEoln Skip to the end of the current line or file
TextFile Declares a file type for storing lines of text
Example code : Show the file position in a binary file
var
myWord, myWord1, myWord2, myWord3 : Word;
myFile : File of Word;
begin
// Try to open the Test.cus binary file in write only mode
AssignFile(myFile, 'Test.cus');
ReWrite(myFile);
// Write a few lines of Word data to the file
myWord1 := 123;
myWord2 := 456;
myWord3 := 789;
Write(myFile, myWord1, myWord2, myWord3);
// 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
Read(myFile, myWord);
// Note - FilePos shows the after read position
ShowMessage('Record '+
IntToStr(FilePos(myFile))+' = '+
IntToStr(myWord));
end;
// Close the file for the last time
CloseFile(myFile);
end;
Show full unit code
Record 1 = 123
Record 2 = 456
Record 3 = 789
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