CompareStringA maps EUDC characters to character positions in the Unicode Private Use Zone and then CompareStringA deals the characters in the Unicode Private Use Zone according to the following schema.
There is a new script member value defined to represent all the code points in the Unicode Private Use Zone. This value should be greater than all other script membership values. The code points within this script membership will have alpha-numeric weights such that they will be sorted in numerical Unicode code point order. They will have no other linguistic weights associated with them. See the NLS API specification for more information on sorting.