Installing Qt4 on Windows - do I need to fully install MingW or just have local copies

Question

That is, can I get away with DLLs in the install directory or does the installer need to ensure that MingW is fully installed?

Answer 1

If you install the Qt SDK, it will actually install its own MinGW tree.

Answer 2

This doesn't directly answer your question, but generally speaking, to ensure I have all the right dependencies when creating an installer, I do the following:

• Use Depends, a Microsoft tool that shows what DLLs a Windows executable (.exe or another .dll) depends on. This will not show dynamically loaded DLLs though, such as QT plugins. I believe Depends is part of the Platform SDK (it used to be, anyway), which you should be able to download. See here for example.
• Use a virtualization tool (like VirtualBox or VMWare) to install a fresh copy of Windows and your application. If it complains of missing DLLs on startup, you missed something in the install package.

You should be aware of any dependencies on the Visual C++ run-time. There are many different versions out there, and if your app depends on them, you need to install the correct version to the Windows\WinSxS directory. Microsoft provides a redistributable for each version of Visual C++ (including the express edition, which you can get for free). I only mention this because I noticed when installing Qt SDK that the VC++ redistributable was getting installed, so the Qt DLLs may have a dependency on the VC++ run-time.