_Load( ) API Library Routine Example
The following example converts to uppercase a string argument passed by reference.
SET LIBRARY TO LOAD
x = "abc"
= XUPPER(@x)
? x
#include <pro_ext.h>
void FAR Upper(ParamBlk FAR *parm)
{
char FAR *pString;
Value val;
int i;
//
// _Load() and _Store are the functions of interest for pass-by-reference.
//
_Load(&parm->p[0].loc, &val);
//
// FoxPro doesn't check the type of pass-by-reference arguments, so we do.
//
if (val.ev_type != 'C')
{
_Error(9); // "Data type mismatch"
}
pString = _HandToPtr(val.ev_handle);
for (i = 0; i < val.ev_length; i++)
{
if ('a' <= *pString && *pString <= 'z')
{
*pString += ('A' - 'a');
}
pString++;
}
_Store(&parm->p[0].loc, &val);
//
// We need to free the handle that we created with _LOAD()
//
_FreeHand(val.ev_handle);
}
FoxInfo myFoxInfo[] =
{
{"XUPPER", (FPFI) Upper, 1, "R"},
};
FoxTable _FoxTable =
{
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};