_HUnLock( ) API Library Routine


void _HUnLock(MHANDLE hand) MHANDLE hand; /* Memory handle. /

_HUnLock( ) doesn't cause memory reorganization.

For more information on how to create an API library and integrate it with Visual FoxPro, see Accessing the Visual FoxPro API.

The following example uses _RetDateStr( ) to return a Visual FoxPro date type, assuming that the character parameter is a proper date. It issues _HUnLock( ) when memory handles no longer need to be locked, because the performance of Visual FoxPro can be adversely affected by locked memory handles.

Visual FoxPro Code

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SET LIBRARY TO HUNLOCK ? DATES("2/16/95") && returns date {02/16/95}

C Code

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#include <pro_ext.h> void FAR dates(ParamBlk FAR parm) { MHANDLE mh; char FAR instring; if ((mh = _AllocHand(parm->p[0].val.ev_length + 1)) == 0) { _Error(182); // "Insufficient memory" } _HLock(parm->p[0].val.ev_handle); instring = _HandToPtr(parm->p[0].val.ev_handle); instring[parm->p[0].val.ev_length] = '\0'; _RetDateStr(instring); _HUnLock(parm->p[0].val.ev_handle); } FoxInfo myFoxInfo[] = { {"DATES", (FPFI) dates, 1, "C"} }; FoxTable _FoxTable = { (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo };

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#include <pro_ext.h>
void FAR dates(ParamBlk FAR *parm)
{
   MHANDLE mh;
   char FAR *instring;
   if ((mh = _AllocHand(parm->p[0].val.ev_length + 1)) == 0) 
   {
      _Error(182); // "Insufficient memory"
   }
   _HLock(parm->p[0].val.ev_handle);
   instring = _HandToPtr(parm->p[0].val.ev_handle);
   instring[parm->p[0].val.ev_length] = '\0';
   _RetDateStr(instring);
   _HUnLock(parm->p[0].val.ev_handle);
}
FoxInfo myFoxInfo[] = {
   {"DATES", (FPFI) dates, 1, "C"}
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};

Reference

_AllocHand( ) API Library Routine
_FreeHand( ) API Library Routine
_GetHandSize( ) API Library Routine
_HandToPtr( ) API Library Routine
_HLock( ) API Library Routine
_MemAvail( ) API Library Routine
_SetHandSize( ) API Library Routine

Other Resources

API Library Construction

Remarks

Example

Visual FoxPro Code

C Code

See Also

Reference

Other Resources