| Description |
The Eoln function returns true if the current file given by FileHandle is positioned at the end of the current line.
The file must have been assigned using AssignFile, and opened with Reset.
The Eoln function is used with the Read procedure to know when the end of the current line has been reached.
More specifically, it is only needed when reading character data - reading numeric data treats the end of line as white space, and skips past it when looking for the next number.
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| Notes |
Warning after reading the last line of a file, Eof will be true, even though data has been read successfully.
So use Eof before reading, to see if reading is required.
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| Related commands |
| Eof |
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Returns true if a file opened with Reset is at the end |
| Read |
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Read data from a binary or text file |
| ReadLn |
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Read a complete line of data from a text file |
| SeekEof |
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Skip to the end of the current line or file |
| SeekEoln |
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Skip to the end of the current line or file |
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| Example code : Reading one character at a time from a text file line |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
// The System unit does not need to be defined
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
myFile : TextFile;
letter : char;
text : string;
begin
// Try to open the Test.txt file for writing to
AssignFile(myFile, 'Test.txt');
ReWrite(myFile);
// Write lines of text to the file
WriteLn(myFile, 'Hello');
WriteLn(myFile, 'To you');
// Close the file
CloseFile(myFile);
// Reopen the file for reading
Reset(myFile);
// Display the file contents
while not Eof(myFile) do
begin
// Proces one line at a time
ShowMessage('Start of a new line :');
while not Eoln(myFile) do
begin
Read(myFile, letter); // Read and display one letter at a time
ShowMessage(letter);
end;
ReadLn(myFile, text);
end;
// Close the file for the last time
CloseFile(myFile);
end;
end.
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| Hide full unit code |
Start of a new line :
H
e
l
l
o
Start of a new line :
T
o
y
o
u
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