MAINSAIL Language Manual, Section 33.28

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33.28. displace

Figure 33–27. displace (GENERIC)
$BUILTIN
ADDRESS
PROCEDURE   displace    (POINTER p;
                         INTEGER n);

$BUILTIN
ADDRESS
PROCEDURE   displace    (POINTER p;
                         LONG INTEGER n);

$BUILTIN
ADDRESS
PROCEDURE   displace    (ADDRESS a;
                         INTEGER n);

$BUILTIN
CHARADR
PROCEDURE   displace    (CHARADR c;
                         INTEGER n);

$BUILTIN
ADDRESS
PROCEDURE   displace    (ADDRESS a;
                         LONG INTEGER n);

$BUILTIN
CHARADR
PROCEDURE   displace    (CHARADR c;
                         LONG INTEGER n);

displace computes an ADDRESS or CHARADR as a displacement from a POINTER, ADDRESS, or CHARADR.

The ADDRESS forms return an ADDRESS that is displaced n storage units from a. No rounding or alignment occurs.

The POINTER forms return an address that is displaced n storage units from p (i.e., displace(p,n) is equivalent to displace(cva(p),n)).

The CHARADR forms return a CHARADR that is displaced n characters from c.

n may be positive or negative. If the resulting ADDRESS or CHARADR would be less than the lowest representable ADDRESS or CHARADR, or greater than the highest representable ADDRESS or CHARADR, the result is undefined; i.e., a program may not assume that ADDRESSes “wrap around” at Zero.

A garbage collection cannot occur during a call to displace.

Example 33–28. Use of displace
INTEGER i;
STRING s;
CHARADR c;

s := "xyz";
c := displace(cvc(s),2);
i := cLoad(c); # i is 'z'

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MAINSAIL Language Manual, Section 33.28