I suppose a fair number of us know this:
However, for those who don't:-
If you are truncating a file, say, to $fileObject->ftruncate(0), then, it may be advisable to call $fileObject->fseek(0) first (before you call '$fileObject->ftruncate').
On inspection, I was encountering 'NULL' characters at the beginning of a, or the, file.
Hence, from what I have surmised; when 'ftruncate()' is called, the file pointer does NOT move to the beginning (or, at least, the required position) of the file.
This issue cost me a fair amount of time to figure out, so I hope it helps someone.
SplFileObject::ftruncate
(PHP 5 >= 5.1.0, PHP 7)
SplFileObject::ftruncate — Truncates the file to a given length
Descrierea
public SplFileObject::ftruncate
( int
$size
) : bool
Truncates the file to size bytes.
Parametri
-
size -
The size to truncate to.
Notă:
If
sizeis larger than the file it is extended with null bytes.If
sizeis smaller than the file, the extra data will be lost.
Valorile întoarse
Întoarce valoarea true în cazul
succesului sau false în cazul eșecului.
Exemple
Example #1 SplFileObject::ftruncate() example
<?php
// Create file containing "Hello World!"
$file = new SplFileObject("/tmp/ftruncate", "w+");
$file->fwrite("Hello World!");
// Truncate to 5 bytes
$file->ftruncate(5);
// Rewind and read data
$file->rewind();
echo $file->fgets();
?>
Exemplul de mai sus va afișa ceva similar cu:
Hello
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User Contributed Notes 1 note
irvinezega at hotmail dot com ¶
6 years ago
