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Question

How to flush output after each `echo` call?

Answer 1

+3 A:

what you want is the flush method. example:

echo "log to client";
 flush();

GSto 2010-06-28 14:29:24

it is a little dirty to put a flush at the end of the echo call...

CuSS 2010-06-28 14:33:07

@CuSS Regardless, this is the only way to satisfy the functionality that you want

Justin Johnson 2010-06-28 15:14:14

what's dirty about it? That's what flush() was designed to do, and it gets the job done.

GSto 2010-06-28 15:41:01

`ini_set('implicit_flush', true)` will basically emulate a flush() after ever output block, and it can get set pretty much anywhere (php.ini, .htaccess, per-script, etc...)

Marc B 2010-06-28 20:47:50

Answer 2

+1 A:

The correct function to use is flush().

<html>
<body>
<p>
Hello! I am waiting for the next message...<br />
<?php flush(); sleep(5); ?>
I am the next message!<br />
<?php flush(); sleep(5); ?>
And I am the last message. Good bye.
</p>
</body>
</html>

Please note that there is a "problem" with IE, which only outputs the flushed content when it is at least 256 byte, so your first part of the page needs to be at least 256 byte.

moontear 2010-06-28 14:34:57

Cool, didn't knew about that IE Bug... Is that any function besides `echo` and `print` that prints directly to the browser?

CuSS 2010-06-28 14:37:04

@CuSS: It's not a bug; it's an "undocumented feature"

amphetamachine 2010-06-28 22:33:06

Answer 3

+2 A:

Why not make a function to echo, like this:

function fecho($string) {
 echo $string;
 ob_flush();
}

cam8001 2010-06-28 14:36:11

Better that @GSto Answer, but I'm searching for something like @amphetamachine Answer... You will get +1 ;)

CuSS 2010-06-28 14:42:19

Answer 4

+1 A:

Edit:

I was reading the commends on the manual page and came across a bug that states that ob_implicit_flush does not work and the following is a workaround for it:

ob_end_flush();

# CODE THAT NEEDS IMMEDIATE FLUSHING

ob_start();

What may even be happening is that the client does not receive the packet from the server until the server has built up enough characters to send what it considers a packet worth sending.

Old Answer:

You could use ob_implicit_flush which will tell output buffering to turn off buffering for a while:

ob_implicit_flush(true);

# CODE THAT NEEDS IMMEDIATE FLUSHING

ob_implicit_flush(false);

amphetamachine 2010-06-28 14:36:19

Yes, definitely I'm looking for something like that (+1), but it didn't worked :s Can it be Apache's fault?

CuSS 2010-06-28 14:38:26

These two comments to that function may help: http://www.php.net/manual/en/function.ob-implicit-flush.php#35072http://www.php.net/manual/en/function.ob-implicit-flush.php#33778

cam8001 2010-06-28 14:44:17

If i stop the flush `ob_end_flush()`, my program skips the important step (don't know why ;s)I've added the line `flush` on my Class `DebugEcho` function, and it didn't workedtoo, besides, it's a little bad and time consuming doing a flush on the cache every `echo` call.

CuSS 2010-06-28 14:54:30

ob_end_flush will clear the buffer and stop output buffering completely, so don't use that until you're sure that you don't want to buffer anymore content!

cam8001 2010-06-28 15:11:15

You still need to `flush()` after each line of output as it is not guaranteed to be sent to the client immediately.

Justin Johnson 2010-06-28 15:14:55

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How to flush output after each `echo` call?

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