XamppHTTPRequest. phprequire_once 'pear. php' solution

XamppHTTPRequest. phprequire_once 'pear. php' I just learned php and used xampp to build the php environment. For more information, see the Request in the php/PEAR/HTTP/directory. php, which contains require_once 'pear. php '; load PEAR according to my personal understanding. ph xampp HTTP Request. php require_once 'pear. php'
I just learned php and used xampp to build the php environment.
For more information, see Request. php in the php/PEAR/HTTP/directory,
There is require_once 'pear. php ';
According to my personal understanding, the loading of PEAR. php should be to load the files in the current directory, that is, the files in the HTTP directory.
However, PEAR. php is not in this directory, but in the PEAR directory.
Could you tell me whether I understand it incorrectly or if there are other settings, such as environment variables,
Thank you for your patience.

------ Solution --------------------
Your understanding is correct.
A sufficient condition for using PEAR is to add the PEAR directory to include_path.