Example 2

 This program demonstrates how to determine the C numeric data type
 for Clipper numeric parameters for use within C.  This version does
 all the data comparisons in the file for illustrative purposes.
 Example 3 uses extend.h style pseudo-functions defined in Number.h to
 hide the details of these comparisons.  This allows a much cleaner
 source file.


 /***
 *   Testnum.prg
 *
 *   By: Scott McIntosh, Nantucket Corp.
 *
 *   Clipper program to test the C function Number()
 */

 #include "set.ch"


 PROCEDURE Main

    LOCAL nVar1 := 123.456        // a float
    LOCAL nVar2 := 123456         // a long
    LOCAL nVar3 := 12345          // an int

    SET( _SET_DECIMALS, 5 )
    SCROLL()

    // the C function Number() displays the type, we then re-display
    // the value returned from Number() value to confirm that Number()
    // converted it to a C variable and back correctly.
    //
    ? nVar1, Number( nVar1 )      // should be a float, value = 123.456
    ? nVar2, Number( nVar2 )      // should be a long,  value = 123456
    ? nVar3, Number( nVar3 )      // should be an int,  value = 12345

 QUIT


 /***
 *   Number.c
 *
 *   By: Scott McIntosh, Nantucket Corp.
 *
 *   Demonstrates how to determine the type of a numeric parameter
 *   received from Clipper.  Normally, once we stored the number
 *   into the proper data type we would do something useful with
 *   it.
 *
 *   This program just displays the parameters numeric type, and
 *   then returns the value back to Clipper to show that we haven't
 *   truncated or corrupted its value.
 *
 *   Compile: cl /AL /c /FPa /Gs /Oalt /Zl number.c
 *      Link: RTLINK FI numtest, number LIB clipper, llibca /NOE
 */

 #include "extend.h"
 #include <limits.h>

 CLIPPER Number( void )
 {
    double dNum;
    long   lNum;
    int    iNum;

    dNum = _parnd(1);
    lNum = _parnl(1);

     // by subtracting the long value of the parameter from the double
     // value of the same parameter, we can determine if it is a floating
     // point number (i.e. if we have any decimal places)
     //
    if( ( dNum - (double) lNum ) != 0 )
    {
       cprintf( "\r\n\n  Double " );
       _retnd( dNum );
    }
    else
    {
       if( (lNum >= INT_MIN) && (lNum <= INT_MAX) )
       {
          // we're small enough to be an int, so we could safely
          // use iNum and be sure its value is correct
          iNum = _parni( 1 );

          cprintf( "\r\n\n  Integer " );
          _retni( iNum );
       }
       else
       {
          // we're too big to be an int, so we stay as a long
          cprintf( "\r\n\n  Long " );
          _retnl( lNum );
       }
    }
    return;
 }

 /* EOF: Example 2 */