Returns the largest integer not less than the receiving string value. The receiving string is first rounded according to standard Rexx rules, as though the operation receiving_string+0 had been carried out. The ceiling is then calculated from that result and returned. The result is never in exponential form. If there are no nonzero digits in the result, any minus sign is removed.

2~ceiling             -->    2
'-2'~ceiling          -->    -2
12.3~ceiling          -->    13
'-12.3'~ceiling       -->    -12
'-0.1'~ceiling        -->    0