XOP Toolkit includes libraries and sample projects for the following development systems:

Mac OS X

Xcode 7

Xcode 8

Xcode 8

Windows

Visual C++ 2015 (express or professional editions)

Visual C++ 2017 (express or professional editions)

Microsoft Visual C++ Express Edition (free) is fine for most XOP development.

Xcode XOP Project

Visual C++ XOP Project