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_SetHandSize( ) API Library Routine

  • Article

Changes the amount of memory allocated to the memory block handle hand.

unsigned short _SetHandSize(MHANDLE hand, unsigned long size)
MHANDLE hand;            /* Memory block handle. */
unsigned int size;            /* New number of bytes. */

Remarks

_SetHandSize( ) returns True (an integer other than 0) if the reallocation is successful, or False (0) if the reallocation fails. The data associated with the MHANDLE is preserved. If hand is a locked MHANDLE, _SetHandSize( ) fails.

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

Example

The following example uses _SetHandSize( ) to change the amount of memory allocated to an MHANDLE.

Visual FoxPro Code

SET LIBRARY TO SETHANDS
= HANDTOPTR("Hello, world.") && displays "Hello, world" on screen

C Code

#include <pro_ext.h>

void NullTerminate(Value FAR *cVal)
{
   if (!_SetHandSize(cVal->ev_handle, cVal->ev_length + 1))
   {
      _Error(182); // "Insufficient memory"
   }
   ((char FAR *) _HandToPtr(cVal->ev_handle))[cVal->ev_length] = '\0';
}

FAR Example(ParamBlk FAR *parm)
{
   NullTerminate(&parm->p[0].val);

   _HLock(parm->p[0].val.ev_handle);
   _PutStr(_HandToPtr(parm->p[0].val.ev_handle));
   _HUnLock(parm->p[0].val.ev_handle);
}

FoxInfo myFoxInfo[] = {
   {"HANDTOPTR", (FPFI) Example, 1, "C"},
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};

See Also

_AllocHand( ) API Library Routine | _FreeHand( ) API Library Routine | _GetHandSize( ) API Library Routine | _HandToPtr( ) API Library Routine | _HLock( ) API Library Routine | _HUnLock( ) API Library Routine | _MemAvail( ) API Library Routine