_MemMove( ) API Library Routine Example
The following example uses _MemMove( ) to implement a substring function. From Visual FoxPro, MEMMOVE(s, n1, n2) returns the substring of s starting from position n1 and through position n2.
SET LIBRARY TO MEMMOVE
? MEMMOVE("Hello, world.", 8, 10) && returns "wor"
#include <pro_ext.h>
FAR Example(ParamBlk FAR *parm)
{
int SubstrLen;
MHANDLE bufferHandle;
char FAR *FirstDest;
SubstrLen = parm->p[2].val.ev_long - parm->p[1].val.ev_long + 1;
if ((bufferHandle = _AllocHand(SubstrLen + 1)) == 0)
{
_Error(182); // "Insufficient memory"
}
_HLock(bufferHandle);
_HLock(parm->p[0].val.ev_handle);
FirstDest = (char FAR *) _HandToPtr(parm->p[0].val.ev_handle) +
parm->p[1].val.ev_long - 1;
_MemMove(_HandToPtr(bufferHandle), FirstDest, SubstrLen);
((char FAR *) _HandToPtr(bufferHandle))[SubstrLen] = '\0';
_RetChar(_HandToPtr(bufferHandle));
_HUnLock(bufferHandle);
_HUnLock(parm->p[0].val.ev_handle);
}
FoxInfo myFoxInfo[] = {
{"MEMMOVE", (FPFI) Example, 3, "C,I,I"},
};
FoxTable _FoxTable = {
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};