A hint for PHP beginners like me:
The buffered output which is write by fflush() has nothing to do with the output buffer which is initiated by the ob_start() function.
fflush
(PHP 4 >= 4.0.1, PHP 5, PHP 7)
fflush — Flushes the output to a file
Descrierea
fflush
( resource
$stream
) : bool
This function forces a write of all buffered output to the resource
pointed to by the file stream.
Parametri
-
stream -
Indicatorul fișierului trebuie să fie valid și trebuie să indice la un fișier deschis cu succes cu ajutorul fopen() sau fsockopen() (și să nu fie închis cu fclose()).
Valorile întoarse
Întoarce valoarea true în cazul
succesului sau false în cazul eșecului.
Exemple
Example #1 File write example using fflush()
<?php
$filename = 'bar.txt';
$file = fopen($filename, 'r+');
rewind($file);
fwrite($file, 'Foo');
fflush($file);
ftruncate($file, ftell($file));
fclose($file);
?>
add a note
User Contributed Notes 2 notes
michaelsy01[NXSPAM] at informantum dot de ¶
5 years ago
jzho327 at cse dot unsw dot edu dot au ¶
21 years ago
Sorry, the note I previously added regarding fflush() has a bug!
when you read file by calling
$fp = fopen("myfile", "a+");
and you wish to read the content, you have to call
rewind($fp) before you attemp to read it. (Silly me) Or else if you tried something like
$fp = fopen("myfile", "a+");
$content = fread($fp);
// show that content is in fact null
if ($content == NULL)
print "but it must be first put to rewind<br>\n";
will result
but it must be first put to rewind.
[new line]
in fact, if you are not careful (like me), and you opened it with
$fp = fopen("myfile", "r+");
$content = fread($fp);
..
// do something with content
..
then you tried to again
$content = fread($fp);
without rewind, you'd get NULL again. This sounds trivial, but if you work with several file resources, with freads and fopens everywhere, you can get easily lost. So becareful.
