In reply to SHIKHA SRIVASTAVA:
The UCIS API is a C language API that helps extract or write information into coverage databases that support the UCIS. Since it is C-API it can either be used in post-sim or in simulation in any env. (e.g. via SystemVerilog DPI/PLI). The API is open source as defined by the standard, the implementation is tool specific. To use the API your simulator needs to support the UCIS API for coverage databases.