(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
ob_get_flush — 冲刷（发送）活动输出处理程序的返回值，返回活动输出缓冲区的内容并将其关闭
该函数调用输出处理程序（使用 PHP_OUTPUT_HANDLER_FINAL
flag），冲刷（发送）其返回值，返回活动输出缓冲区的内容并关闭活动输出缓冲区。
如果没有以 PHP_OUTPUT_HANDLER_REMOVABLE flag 启动的活动输出缓冲区，ob_get_flush() 将失败。
ob_get_flush() 将冲刷（发送）输出处理程序的返回值，即使活动输出缓冲区是在没有
PHP_OUTPUT_HANDLER_FLUSHABLE flag 的情况下启动的。
此函数没有参数。
成功时返回活动输出缓冲区的内容，失败时返回 false。
如果函数失败生成 E_NOTICE。
示例 #1 ob_get_flush() 示例
<?php
// 使用 output_buffering=On
print_r(ob_list_handlers());
// 保存缓冲区到文件
$buffer = ob_get_flush();
file_put_contents('buffer.txt', $buffer);
print_r(ob_list_handlers());
?>以上示例会输出：
Array
(
[0] => default output handler
)
Array
(
)
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 userI 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 errorCorrection 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();
?>