VARPTR and VARSEG Functions Programming Example
 
For examples of how to use the VARPTR and VARSEG functions with other
statements, see
 
  the <BSAVE AND BLOAD PROGRAMMING EXAMPLES>,
  the <CALL ABSOLUTE PROGRAMMING EXAMPLE>, or
  the <CALL INTERRUPT> programming example.
 
This example program illustrates how to use the VARPTR and VARSEG
functions in a CALL statement to pass a BASIC array to a C function.
 
'*** Programming example: VARPTR and VARSEG with CALL ***
'
' Do not attempt to run this program unless you have already
' separately compiled the C function with the large-model (/AL)
' switch and placed the object module in a Quick library or linked
' it to the BASIC main program.
'
' BASIC main program passing an array to C function.
'
DEFINT A-Z
'
DECLARE SUB AddArr CDECL (BYVAL Offs, BYVAL Segm, BYVAL Num)
DIM A(1 TO 100) AS INTEGER
' Fill the array with the numbers 1 to 15.
FOR I=1 TO 15
   A(I)=I
NEXT I
'
' Call the C function. AddArr expects a far address (segment
' and offset). Because CDECL puts things on the stack from
' right to left, put the offset ( VARPTR(A(1)) ) first in the
' list, followed by the segment ( VARSEG(A(1)) ).
'
CALL AddArr(VARPTR(A(1)),VARSEG(A(1)),15%)
'
' Print the modified array.
FOR I=1 TO 15
   PRINT A(I)
NEXT I
 
END
 
/* Add one to the first num elements of array arr.*/
void far addarr(arr,num)
int far *arr;
int num;
{
   int i;
   for(i=0;i<num;i++) arr[i]++;
}