This directive tells the compiler the minimum number of bytes it should use when storing enumerated types. It is of the following form:
{$PACKENUM xxx}
{$MINENUMSIZE xxx}
Where the form with $MINENUMSIZE is for Delphi compatibility. xxx can be one of 1,2 or 4, or NORMAL or DEFAULT (or 0).
The default enumeration size depends on the compiler mode:
In Delphi and TP mode, the size is 1.
In MacPas mode, the size is 2.
In all other modes, the default is 4.
As an alternative form one can use {$Z1}, {$Z2}{$Z4}. The {$Z} form takes a +/- argument, where + is equivalent to {$Z4} and - is equivalent to {$Z1}.
So the following code
{$PACKENUM 1}
Type
Days = (monday, tuesday, wednesday, thursday, friday,
saturday, sunday);
will use 1 byte to store a variable of type Days, whereas it normally would use 4 bytes. The above code is equivalent to
{$Z1}
Type
Days = (monday, tuesday, wednesday, thursday, friday,
saturday, sunday);
or equivalent to
{$Z-}
Type
Days = (monday, tuesday, wednesday, thursday, friday,
saturday, sunday);