fflush

(PHP 4 >= 4.0.1, PHP 5, PHP 7)

fflushFlushes the output to a file

설명

bool fflush ( resource $handle )

This function forces a write of all buffered output to the resource pointed to by the file handle.

인수

handle

파일 포인터는 fopen(), fsockopen()을 통하여 성공적으로 열려, fclose()로 닫지 않은 유효한 파일이여야 합니다.

반환값

성공 시 TRUE를, 실패 시 FALSE를 반환합니다.

예제

Example #1 File write example using fflush()

<?php
$filename 
'bar.txt';

$file fopen($filename'r+');
rewind($file);
fwrite($file'Foo');
fflush($file);
ftruncate($fileftell($file));
fclose($file);
?>

참고

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User Contributed Notes 2 notes

up
1
michaelsy01[NXSPAM] at informantum dot de
11 months ago
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.
up
-3
jzho327 at cse dot unsw dot edu dot au
16 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.
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