User code allows STAR-CCM+ to be customized with functions written in a compiled language such as C, C++ or Fortran. User code takes the form of one or more user libraries attached to STAR-CCM+, each of which contains one or more user functions and a library registration function. Once a user library has been attached, its user functions are available for use and will be provided in drop-down lists for any operation that needs them, notably to specify values on a region or a boundary, initialization and visualization.
User functions can only be accessed on a part if the data used to define the user function exists on that part. For the data to exist it must be allocated on the specific part and must have been initialized.
The status of user code may be viewed in the User Code node under Tools in the object tree, which shows the user libraries currently attached.