what is an environment variable

[Joshua Slive <jo...@slive.ca>]

There was discussion on new-httpd about a month ago that suggested that
the environment manipulation directives were not clear in that they did
not differentiate between what apache calls an environment variable and
what the operating system calls an environment variable.  I believe the
specific example was someone using a module to connect to a database that
required a particular env variable to be set.  SetEnv will not do this.

Below is my suggestion for a way to clarify this in the env.html
documentation.  I will commit it if I don't hear any suggestions or
complaints in the next day.

Joshua.

===================================================================
RCS file: /home/cvs/httpd-docs-1.3/htdocs/manual/env.html,v
retrieving revision 1.16
diff -u -d -b -r1.16 env.html
--- env.html    2001/01/09 03:21:42     1.16
+++ env.html    2001/05/04 19:55:34
@@ -15,11 +15,23 @@
 <!--#include virtual="header.html" -->
 <h1 align="center">Environment Variables in Apache</h1>

-<p>Many operating systems provide a facility for storage and
-transmission of information called environment variables.  Apache uses
-environment variables in many ways to control operations and to
-communicate with other programs like CGI scripts.  This document
-explains some of the ways to use environment variables in Apache.</p>
+<p>The Apache HTTP Server provides a mechanism for storing information
+in named variables that are called <em>environment variables</em>.
+This information can be used to control various operations such as
+logging or access control.  The variables are also used as a mechanism
+to communicate with external programs such as CGI scripts.  This
+document discusses different ways to manipulate and use these
+variables.</p>
+
+<p>It is important to note that, although these variables are referred
+to as <em>environment variables</em>, they are not the same as the
+environment variables controlled by the underlying operating system.
+Instead, these variables are stored and manipulated in an internal
+Apache structure.  They only become actual operating system
+environment variables when they are provided to CGI scripts and Server
+Side Include scripts.  If you wish to manipulate the environment that
+the server itself runs under, you must use the standard environment
+manipulation mechanisms provided by your operating system shell.</p>

 <ul>
 <li><a href="#setting">Setting Environment Variables</a></li>



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