After a few failure, here are the steps. Please not this is for Qt 4.5 only:

1. If you don’t have Qt already, go download it at http://www.qtsoftware.com/downloads

2. Download OpenSSL here http://www.openssl.org/source/You can build it by following the instructions or get the binaries.

3. In command line, go to your Qt folder, configure the build with

configure -openssl -I:path_to_openssl_include_folder -L:path_to_openssl_library_folder

If you want the OpelSSL libraries linked, use “-openssl-link” instead.

4. Then you can start compiling with “make” or “nmake” depending on your OS.

To design such system, the following steps are considered:

1. A server that contains the latest version and a list of updated files.
2. The application should connect to the server to retrieve the list and compare the versions.
3. If there is a new version, download the updated files to replace the new ones.
4. Clean up.

Let’s work on it step-by-step. To save space, I will only post relevant code:

1. Server Side

The directory set up is as the following:

I used an XML file latest.xml to store the version and file list. It’s pretty self-explanatory.

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE XML>
<appname>
	<version>
		<version value="0.5.1" />
	</version>
	<files>
		<file value="app.exe" />
                <file value="some.dll" />
                <file value="another.dll" />
	</files>
</appname>