Include works, readfile doesn't

I'm experiencing odd behaviour loading a html file. require_once, include etc. works:

require_once 'suche.htm';

but readfile or file_get_contents won't

return file_get_contents('suche.htm');

Warning: readfile(suche.htm): failed to open stream: No such file or directory in /var/www/vhosts/h...

Solution

Description
int readfile ( string $filename [, bool $use_include_path = false [, resource $context ]] )

Note the second argument

use_include_path
You can use the optional second parameter and set it to TRUE, if you want to search for the file in the include_path, too.

file_get_contents has the same argument.

You would need to set that to true if you want readfile / file_get_contents to use the same path resolution as require / include.

Note, readfile does not return a string so you cannot use the result in htmlentities

In my opinion, it's much better to use an explicit file path, relative to the current PHP script file. For example

file_get_contents(__DIR__ . '/../suche.htm');