This is the top-level container element for every wxs file. Amongst the possible children, the Product, Module, and PatchCreation elements are analogous to the main function in a C program. There can only be one of these present when linking occurs. Product compiles into an msi file, Module compiles into an msm file, PatchCreation compiles into a pcp file. The Fragment element is an atomic unit which ultimately links into either a Product, Module, or PatchCreation. The Fragment can either be completely included or excluded during linking.

• PatchCreation (min: 0, max: 1)
• Sequence (min: 1, max: 1)
  1. Choice of elements (min: 0, max: 1)
     • Module (min: 0, max: 1)
     • Product (min: 0, max: 1)
  2. Fragment (min: 0, max: unbounded)