[Qt-interest] Licensing

[Paul Miller]

On 6/4/2010 10:46 AM, Finley Lee wrote:
> It is also difficult to use Qt in a plug-in for a Windows application.  I'm talking about plug-ins for applications like web browsers and image editors, not Qt plug-ins.
>
> If you want to use a shared build of Qt in this situation, you can put your DLLs in one of three places:
>
> * Install them in the path.  This may be the best choice but you have to make sure your DLL names won't conflict with other builds of Qt.  I believe the 'infix' config option can help with this.  If the path changes your application can break.  Also, if you have lots of plug-ins using different versions of Qt, you'll end up with a confusing jumble of files.
>
> * Install in \Windows\System32 or \Windows\System.  I believe Microsoft recommends against this, but it could work.  The same concerns as putting the Qt DLLs in the path apply.
>
> * Install next to the host application's binary.  This isn't a good choice because there may be multiple host application that use the same plug-in.  Also, it seems like an unsafe practice to put any files at all in another vendors application directory.  Your application can break if the user installs a new plug-in host.

You can also build a "stub" plugin that simply loads the "real" DLL 
which DOES link with Qt (and other) DLLs. Use the "ALTERED_PATH" flag on 
your dll load call and now you can drop all your support stuff in your 
own directory.