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Article Q68663
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 Passing Basic Numeric Arrays from Basic to C and Back to Basic - Q68663
 
 The following example demonstrates how to pass numeric arrays from
 compiled BASIC to Microsoft C then back to BASIC using BASIC's "by
 reference" calling convention.
 
 More Information:
 
 The example listed below differs from the other Basic-to-C
 array-passing examples in that the example below lets you pass array
 data from BASIC to C then back to BASIC. Other Basic-to-C examples
 pass array data from Basic to C, but not back to Basic.
 
 Code Example
 ============
 
 Compile and link the sample programs below as follows:
 
    BC /O ByRefB.BAS ;
    CL /c /W3 /AM ByRefC.C
    LINK /NOE ByRefB ByRefC ;
 
 ByRefB.BAS
 ----------
 
 ' Declare the BASIC and C routines to use the same calling
 ' convention. In this case we want the default Basic "BY REFERENCE"
 ' calling convention.
 
 DECLARE SUB BTest (Array1%(), Array2!(), Array3#(), Array4&())
 DECLARE SUB CTest (Array1%(), Array2!(), Array3#(), Array4&())
 ' $STATIC
 DIM A%(10), B!(10) ' Define some STATIC data in "DGROUP".
 ' $DYNAMIC
 DIM C#(10), D&(10) ' And, some DYNAMIC data.
 CLS
 FOR i% = 0 TO 10   ' Initialize the arrays.
     A%(i%) = i%
     B!(i%) = .5 * i%
     C#(i%) = 1.5 * i%
     D&(i%) = i% * i%
 NEXT i%
 CTest A%(), B!(), C#(), D&()
 PRINT A%(10), B!(10), C#(10), D&(10)
 END
 SUB BTest (Array1%(), Array2!(), Array3#(), Array4&())
     PRINT
     FOR i% = 0 TO 10
         PRINT Array1%(i%), Array2!(i%), Array3#(i%), Array4&(i%)
     NEXT i%
 END SUB
 
 ByRefC.C
 --------
 
 #include <stdio.h>
 
 /**
  ** Use "typedef" to reduce complexity/readability of code.
  **
  ** BASIC's BY REFERENCE is a near handle to a far pointer for the
  ** actual data of numeric arrays.
  **/
 typedef int    far * near * HInt ;
 typedef long   far * near * HLng ;
 typedef float  far * near * HSng ;
 typedef double far * near * HDbl ;
 
 /**
  ** Define the BASIC routine as a "standard BASIC" call so the
  ** parameters will be the same.
  **/
 extern void pascal BTest ( HInt, HSng, HDbl, HLng ) ;
 
 /**
  ** Define our C routine as a "standard BASIC" routine so we look
  ** like BASIC. This simplifies the parameter passing since we
  ** all look the same on the stack.
  **/
 void pascal CTest (HInt IntArray, HSng SngArray,
                    HDbl DblArray, HLng LngArray)
     {
         int j, i;
         printf ("\Original Array Values\") ;
         BTest ( IntArray, SngArray, DblArray, LngArray ) ;
         for (i = 0, j = 10; i < 6; i++, j--)
             {
                 (*IntArray)[i] = (*IntArray)[j] ;
                 (*LngArray)[i] = (*LngArray)[j] ;
                 (*SngArray)[i] = (*SngArray)[j] ;
                 (*DblArray)[i] = (*DblArray)[j] ;
             }
      printf ("\Modified Array Values\") ;
         BTest ( IntArray, SngArray, DblArray, LngArray ) ;
         printf ("\Modified Last Array Elements\") ;
         (*IntArray) [10] = (int)    3 ;
         (*SngArray) [10] = (float)  4.45 ;
         (*DblArray) [10] = (double) 30.303 ;
         (*LngArray) [10] = (long)   445 ;
     }
 
 Program Output
 ==============
 
  Original Array Values
 
   0             0             0             0
   1             .5            1.5           1
   2             1             3             4
   3             1.5           4.5           9
   4             2             6             16
   5             2.5           7.5           25
   6             3             9             36
   7             3.5           10.5          49
   8             4             12            64
   9             4.5           13.5          81
   10            5             15            100
 
  Modified Array Values
 
   10            5             15            100
   9             4.5           13.5          81
   8             4             12            64
   7             3.5           10.5          49
   6             3             9             36
   5             2.5           7.5           25
   6             3             9             36
   7             3.5           10.5          49
   8             4             12            64
   9             4.5           13.5          81
   10            5             15            100
 
  Modified Last Array Elements
 
   3             4.45          30.303        445