Question

Reading data is performed in 3 steps:

1. A design object must be selected for traverse access from a database (or from memory).
2. Indicate the intent to access data. This is typically done by a vpi_load_init() call as a hint from the user to the tool on which areas of the design are going to be accessed. The tool shall then load the data in an invisible fashion to the user (for example, either right after the call, or at traverse handle creation, or usage). Alternatively, if the user wishes he can (also) choose to add a specific vpi_load() call (this can be done at any point in time) to load, or force the load of, a specific object or collection of objects. This can be done either instead of, or in addition to, the objects in the scope or collection specified in vpi_load_init()). vpi_unload() can be used by the user to force the tool to unload specific objects. It should be noted that traverse handle creation shall fail for unloaded objects or collections.
3. Once an object is selected, and marked for load, a traverse object handle can be created and used to traverse the design objects’ stored data.
4. At this point the object is available for reading. The traverse object permits the data value traversal and access.