ISO Pascal reference manual

*ERROR 111 PRED needs a parameter of a type which defines
a range of values
The parameter given to PRED may only be of an ordinal type, that is
integer, char, boolean, an enumerated type or a subrange.
PROGRAM fail;
VAR val : real;
BEGIN
END.
val := PRED(val);
*ERROR 112 -- SUCC needs a parameter of a type which defines
a range of values
The parameter given to SUCC may only be of an ordinal type, that is
integer, char, boolean, an enumerated type or a subrange.
PROGRAM fail;
VAR val : real;
BEGIN
END.
val := SUCC(val);
*ERROR 113 -- TRUNC needs a real type parameter
The parameter given to TRUNC must be of real type. Note that even
though an integer value can often be used in the context of a real value the
standard does not permit integer parameters for TRUNC.
PROGRAM fail;
VAR x : real;
BEGIN
END.
n, m : integer;
x := 1.54;
m := TRUNC(x);
n := TRUNC(m); [sadly, not permitted}
m := TRUNC(TRUE); [just rubbish}
84 Pascal Issue 1