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/*
 *  $Id: lib-overview.tmpl,v 1.10 2004/06/29 15:13:15 sbooth Exp $
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 *  Copyright (C) 1996 - 2004 Stephen F. Booth <sbooth@gnu.org>
 *  Part of the GNU cgicc library, http://www.cgicc.org
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/*! \page lib_overview Library Overview

The GNU %cgicc library contains classes divided into two broad groups, CGI
classes and response generation classes.

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<div class="header">CGI classes</div>
<div class="subsection">
\endhtmlonly

CGI classes are used to query and manipulate CGI data, including
information on the HTTP server, the current request, and the submitted
form data.
 
cgicc::Cgicc is the main class of the %cgicc library.  It is used to
retrieve information on specific HTML form elements (such as checkboxes,
radio buttons, and text fields), on uploaded files, and to save,
restore, and retrieve information on the CGI environment.

cgicc::CgiEnvironment encapsulates the data passed from the HTTP server
to the CGI application.  This includes all environment variables set by
the HTTP server specified in the CGI standard.

cgicc::FormEntry is an immutable class representing a single user entry
in an HTML form element such as a text field, a radio button, or a
checkbox.  A FormEntry is essentially a name/value pair, where
the name is the name of the form element as specified in the HTML form
itself, and the value is user-entered or user-selected
value. FormEntry provides methods allowing access to the value as
a string, integer, or double.

cgicc::FormFile is an immutable class representing a file uploaded via
the HTTP file upload mechanism.  A FormFile is very similar to a
FormEntry, but does not provide the numerous methods for
accessing the value as different types.

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</div>
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<div class="header">Response generation classes</div>
<div class="subsection">
\endhtmlonly

Response generation classes are used to generate responses to a CGI
query. Generally, the response will consist of one or more HTTP
headers followed by HTML text, but the CGI application may return data
of any type. The response generation classes are subdivided into two
groups:

<ol>
<li><em>HTTP header classes</em><br>
HTTP header classes are used to indicate to the client information on
the data being returned as a result of the CGI request.  For example,
standard HTTP headers indicate the type, size, and modification date of
the transmitted data.<br>

An cgicc::HTTPCookie is a name/value pair used to store a piece of
information about the caller using the caller's own machine.  Cookies
are often used as a means to identify users.  Any of %cgicc's header
classes may contain an arbitrary number of cookies.

cgicc::HTTPHeader is the base class for all simple HTTP headers.  It
is rarely used directly; instead, use one of the provided subclasses.

cgicc::HTTPContentHeader is a subclass of cgicc::HTTPHeader used to
indicate the type of data returned to the client by the CGI application.

cgicc::HTTPRedirectHeader is a subclass of cgicc::HTTPHeader used to
redirect the client to a different URL.

cgicc::HTTPStatusHeader is a subclass of cgicc::HTTPHeader used to
return a 3-digit HTTP status code and the associated message.

cgicc::HTTPHTMLHeader is a subclass of cgicc::HTTPContentHeader used for
data of MIME type \c text/html.

cgicc::HTTPPlainHeader is a subclass of cgicc::HTTPContentHeader used
for data of MIME type \c text/plain.

cgicc::HTTPResponseHeader is a more powerful, generic HTTP header
class used to construct a full HTTP response.
</li>

<li><em>HTML generation classes</em><br>
HTML generation classes are used to generate an HTML response
following any HTTP headers.  To be compliant with the HTML 4.0 standard,
the response must consist of three parts (For a complete
description see the HTML 4.0 specification at 
http://www.w3.org/TR/REC-html40/):

<ul>
<li>A line containing the HTML version information</li>
<li>A declarative header section (delimited by the \c head element)</li>
<li>A body, which contains the document's actual content</li>

The %cgicc library provides one class for each HTML element defined in
the HTML 4.0 specification.  In all cases, the name of the class
corresponds to the name of the HTML element.  %cgicc tries to produce
SGML (and therefore XML) compliant output- thus, atomic elements such
as \c br as rendered as \c \<br />.

There are two special HTML classes defined by %cgicc:

cgicc::HTMLDoctype is used to specify the HTML version information as
required by the HTML 4.0 standard

cgicc::comment is used to indicate an HTML comment
</ul></li></ol>
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</div>
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<div class="nav">
\endhtmlonly
Previous: \ref cgi_overview | 
Current: \ref lib_overview | 
Next: \ref cgicc_tutorial
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</div>
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*/
