These functions are only relevant in the body of a report function (one following a REPORT statement). Only within the report-generating code is the idea of a current page or line meaningful. You can make these values available outside a report through global variables. For example, you could put a statement such as this one in the PAGE HEADER control block:
LET CURR_PAGE = PAGENO
This would assign the current page to a global variable (called CURR_PAGE in the example) that could be tested by code outside the report function.