_Evaluate( ) API Library Routine Example
The following example has the same functionality as the Visual FoxPro EVALUATE( ) function.
SET LIBRARY TO EVALUATE
? XEVAL("2 + 3")
? XEVAL("'a' + 'b'")
? XEVAL("SIN(PI()/2))")
#include <pro_ext.h>
FAR EvaluateEx(ParamBlk FAR *parm)
{
char FAR *expr;
Value result;
// Null terminate character string
if (!_SetHandSize(parm->p[0].val.ev_handle,
parm->p[0].val.ev_length + 1))
{
_Error(182); // "Insufficient memory"
}
_HLock(parm->p[0].val.ev_handle);
expr = (char FAR *) _HandToPtr(parm->p[0].val.ev_handle);
expr[parm->p[0].val.ev_length] = '\0';
_Evaluate(&result, expr);
_RetVal(&result);
_HUnLock(parm->p[0].val.ev_handle);
}
FoxInfo myFoxInfo[] = {
{"XEVAL", (FPFI) EvaluateEx, 1, "C"},
};
FoxTable _FoxTable = {
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};