How to use the obOutput Buffer output buffer function in php

From: http://bbs.phome.net/ShowThread/?threadid=9247&forumid=2
In PHP programming, we often encounter some functions that directly generate output, such as passthru(), readfile(), var_dump() etc. But sometimes we want to import the output of these functions into a file, or process it first and then output it, or process the output of these functions as a string.
At this time we have to use the Output Buffer function .
There are several main functions that handle output buffering:
ob_start() starts output buffering. At this time, PHP stops output. After this, the output is transferred to an internal buffer.
ob_get_contents() This function returns The contents of the internal buffer. This is equivalent to turning these outputs into strings.
ob_get_ length() Returns the length of the internal buffer.
ob_end_flush() Ends the output buffer and outputs the contents of the buffer. After this, the output is It is normal output.
ob_end_clean() Ends the output buffer and throws away the contents of the buffer.
For example, the var_dump() function outputs the structure and content of a variable, which is very useful during debugging.
But if the variable There are HTML special characters such as < , > in the content, which will be invisible when output to the web page. What should I do?
This problem can be easily solved by using the output buffer function.
ob_start();
var_dump($var );
$out = ob_get_contents();
ob_end_clean();
The output of var_dump() is already in $out. You can output it now:
echo '

' . htmlspecialchars($out) . '

The above introduces how to use the obOutput Buffer output buffer function in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.