Includes with muli-level directories

[FP]

I have the following files;
\A.php
\F1\B.php
\F1\F1_1\C.php

File A has the lines "echo 'A'; include_once('F 1/B.php');"
File B has the lines "echo 'B'; include_once('F 2/C.php');"
File C has the line "echo 'C';"

If I open file A in my browser I get "ABC".
If I open file B in my browser I get "BC".
So far so good.
I also have files;
\D.php
\F1\E.php
\F1\F1_1\F.php

File D has the lines "echo 'D'"
File E has the lines "echo 'E'; include_once('. ./D.php');"
File F has the line "echo 'F'; include_once('. ./E.php');"

If I open file E in my browser I get "ED".
If I open file F in my browser I get "FE" and an error saying file D
doesn't exist.
If I change the include portion of file E to '../../D.php' then I get
"FED".

Is this how PHP is suppose to work?
I have several files at the root level including a "SetupData. php" file
in which I need to specify IPs, passwords etc.
I have a directory "FX" and the file "ImageProxy.php " inside it.
The "ImageProxy.php " file is used as an include by files at the root
level but also called directly.
The "ImageProxy.php " file requires passwords stored in the
"SetupData. php" file.
How do I get the "ImageProxy.php " file to access the variables in the
"SetupData. php" file?
As far as I can tell it's possible to include a file by full path, if
possible I would like to avoid that, are there any other ways?

[AlexVN]

FP wrote:

I also have files;
\D.php
\F1\E.php
\F1\F1_1\F.php

File D has the lines "echo 'D'"
File E has the lines "echo 'E'; include_once('. ./D.php');"
File F has the line "echo 'F'; include_once('. ./E.php');"

If I open file E in my browser I get "ED".
If I open file F in my browser I get "FE" and an error saying file D
doesn't exist.

Please check the PHP manual on include function:
"If filename begins with ./ or ../, it is looked only in include_path
relative to the current working directory."
Please use the http://www.php.net/getcwd in your D,E,F scripts to check
what is current directory. I suspect that when the E.php is evaulated
in context of E.php, the working directory is still \F1\F1_1 so the
include_once('. ./D.php'); is trying to include \F1\F1_1\..\D.p hp, which
is does not exist.

Sincerely,
Alexander
http://www.alexatnet.com

[FP]

AlexVN wrote:

Please use the http://www.php.net/getcwd in your D,E,F scripts to check
what is current directory. I suspect that when the E.php is evaulated
in context of E.php, the working directory is still \F1\F1_1 so the
include_once('. ./D.php'); is trying to include \F1\F1_1\..\D.p hp, which
is does not exist.

You're right, just tried the "getcwd" command and the working directory
for all three files was always \F1\F1_1\

Thanks