Php在file_get_contents中不清楚$ use_include_path的定义

Question

As I was looking on http://php.net/manual/en/function.file-get-contents.php for the file_get_contents function, I noticed that it takes an optional second parameter named $use_include_path but I cannot understand what is the use and how changes the file_get_contents behavior.

Can you provide me an example in order to understand it better?

Answer 1

For example, I have file /tmp/code.txt and I need to get contents of this file, I can write something like:

var_dump(file_get_contents('code.txt'));

but it will fall with error (No such file or directory), hence I have to profile full path to file, but in case I don't want to do it, I can write something like:

set_include_path(get_include_path() . PATH_SEPARATOR . '/tmp/');
var_dump(file_get_contents('code.txt', FILE_USE_INCLUDE_PATH));

and it will work!

It is very useful in case you have library or sub-project or you mount your sub-project into another project or you have SDK or something else...
and you can have set_include_path in your bootstrap script for your module/library/whatever but in your code, you have only clear usage of particular files without full path, only relative...