def _uptime_riscos():
try:<EOL><INDENT>up = swi.swi('<STR_LIT>', '<STR_LIT>')<EOL>if up < <NUM_LIT:0>:<EOL><INDENT>return None<EOL><DEDENT>return up / <NUM_LIT><EOL><DEDENT>except NameError:<EOL><INDENT>return None<EOL><DEDENT>
Returns uptime in seconds or None, on RISC OS.