User functions are functions or subroutines written in a compiled language such as C, C++ or Fortran. Each function can request arguments from STAR-CCM+ and must return a result consistent with its type. The two principal categories of user functions are:
In order for STAR-CCM+ to know which arguments to pass to a user function and what type of result to expect, the user function must be registered using a library registration function. Available user functions can then be viewed in the user library nodes in the User Code node under Tools in the object tree.
The display name for the user function, together with its Type, its Args and their Sizes, is obtained from the library registration function.