The problem you see could be due to the specifics of how Fluent compiles the library. When you compile a library and then try to compile another UDF code under a different name, this operation doesn’t always automatically purge libudf library of the previous coding, and the new code is added to the library. As a result, you can get a conflict in what compiled UDF macros get hooked to the code. To avoid this issue, it is suggested to completely delete libudf library before compiling a new code.