ob_get_flush()

(PHP 4 >= 4.3.0, PHP 5, PHP 7)

刷出（送出）缓冲区内容，以字符串形式返回内容，并关闭输出缓冲区。

说明

ob_get_flush(void): string

ob_get_flush()刷出（送出）缓冲区内容，以字符串形式返回内容，并关闭输出缓冲区。

Note:这个函数与ob_end_flush()相似，不同的是本函数还会以字符串形式返回缓冲区内容。

返回值

返回输出缓冲区的内容；或者是，如果没有起作用的输出缓冲区，返回FALSE。

范例

Example #1ob_get_flush()example

<?php
//using output_buffering=On
print_r(ob_list_handlers());
//save buffer in a file
$buffer = ob_get_flush();
file_put_contents('buffer.txt', $buffer);
print_r(ob_list_handlers());
?>

以上例程会输出：

Array
(
    [0] => default output handler
)
Array
(
)

参见

ob_end_clean() 清空（擦除）缓冲区并关闭输出缓冲
ob_end_flush() 冲刷出（送出）输出缓冲区内容并关闭缓冲
ob_list_handlers() 列出所有使用中的输出处理程序。

Hi,
this is just to add a behavior that I haven't understud at first place.
ob_get_flush actually returns the content of the buffer as a text but also it sends the buffer back to the browser so that it's displayed on user screen.
Use ob_get_clean if you do not want the buffer to be send to the user

Correction to previous post: ob_get_clean() is better, ie:
<?php
// start generating html
$html = '<html><head>'; // etc
// start output buffering
ob_start();
// call function which outputs immediately
print_menu();
// append this to $html and empty buffer
$html .= ob_get_clean();
?>

I found this function is useful for storing output instead of displaying it. For example, I wanted to use an old function which echoed the ouput but I wanted it in a variable, not outputted immediately. Here's how:
<?php
// start generating html
$html = '<html><head>'; // etc
// start output buffering
ob_start();
// call function which outputs immediately
print_menu();
// append this to $html
$html .= ob_get_flush();
// empty output buffer
ob_clean();
?>

I don't know how exactly this works, but if you call this function, PHP would behave as if headers have been sent (even though the output has gone to a string).
This means that you can't call this function, and then call setcookie for example.
This was verified by trial and error