P_CONC_REQUEST_ID and Importance

-- In some report you need to show the Concurrent Request ID too on the report and while you calling SRWINIT in user exist in before report trigger must need to create P_CONC_REQUEST_ID.

--The concurent Manager passes the concurent request id into p_conc_request_id while running the concurrent program.
When you call the FND SRWINIT user exit in the report's Before Report trigger, the user exit uses the passed request id to query the
Oracle Applications context that the concurrent request was submitted in
(via the FND_CONCURRENT_REQUESTS table) and then log on with that context.
This allows you to use operating specific views, access profile option values, etc
within your report. You should also call the FND SRWEXIT user exit in the After Report trigger.

If you try calling the FND SRWINIT user exit in your report without the P_CONC_REQUEST_ID
parameter defined as a user parameter on your report, the user exit will fail.

The "Coding Oracle Reports Concurrent Programs" chapter of the Applications Developer's Guide has
the details (along with a warning that at some point this method may change)