Function _paratype() | Xbase++

Determines the type of an array element in a multidimensional array.

ULONG _paratype(XppParamList pList, ULONG ulIndex, ...);

XppParamList pList

Pointer to the Xbase++ parameter list, which is used to provide access to the parameter.

ULONG ulIndex

Position within the parameter list (first position is 1) of the array parameter whose element is to be checked for type.

...

The remaining arguments must be of the ULONG type and determine the array element in a multidimensional array. An index is specified per array dimension. The end of the array index list must be indicated by incorporating a NULL as the last value in the list (if the first index is NULL, the function works like _partype()).

Returns the array element type. If ulIndex is referencing a parameter that is not an array then XPP_ILLEGAL is returned.

_paratype() in connection with _paralen() determines the structure and size of multidimensional arrays. If the first array index of _paratype() is NULL, the type of the parameter is returned. If indexes not equal to NULL are passed, the parameter must be an array and the return value describes the type of the specified element. In CA-Clipper, the function _parinfa() is used to determine similar information, but it does not support multidimensional arrays.

It should be noted that for some types more then one bit is masked in the return value. Furthermore, the numeric value representing a type may change in future Xbase++ versions. Because of these reasons the return value should be tested with one of the macros defined in the header file xpppar.h. The following table lists the macros and the types for which the macro evaluates to true:

Macro	Type	Meaning
XPP_IS_UNDEF()	XPP_UNDEF	NIL
XPP_IS_CHAR()	XPP_CHARACTER or XPP_MEMO	Character string
XPP_IS_MEMO()	XPP_MEMO	Memo character string
XPP_IS_NUM()	XPP_NUMERIC or XPP_DOUBLE	Numeric
XPP_IS_FLOAT()	XPP_DOUBLE	Floating point
XPP_IS_LOGIC()	XPP_LOGICAL	Logical
XPP_IS_DATE()	XPP_DATE	Date
XPP_IS_ARRAY()	XPP_ARRAY	Array
XPP_IS_BLOCK()	XPP_BLOCK	Code block
XPP_IS_OBJECT()	XPP_OBJECT	Object

Since the elements of an array in Xbase++ are permitted to have different types, each element should be explicitly tested before its value is accessed.

/* 
Copies the first 10 characters of a character string in a two 
dimensional array 
*/ 
#include <xpppar.h> 

ULONG   num = 1; 
ULONG   len; 
CHAR    buffer[10]; 
                    /* Is the first parameter an array? */ 
if ( XPP_IS_ARRAY( _paratype(<pList>, num, 0) ) ) 
{ 
                    /* Is first element also an array? */ 
if ( XPP_IS_ARRAY( _paratype(<pList>, num, 1, 0) ) ) 
{ 
                    /* Is first element of the subarray a string? */ 
   if ( XPP_IS_CHAR( _paratype(<pList>, num, 1, 1, 0) ) ) 
   { 
                    /* copy string */ 
      len = _parc(buffer, sizeof(buffer), <pList>, num, 1, 1, 0); 
   } 
} 
}

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Function _paratype() Foundation