LocalReAlloc
The LocalReAlloc
function changes the size or the attributes of a specified local memory object.
The size can increase or decrease.
HLOCAL LocalReAlloc(
|
HLOCAL hMem, |
// handle of local
memory object |
|
UINT uBytes, |
// new size of
block |
|
UINT uFlags |
// how to
reallocate object |
|
); |
|
Parameters
hMem
Identifies
the local memory object to be reallocated. This handle is returned by either
the LocalAlloc
or LocalReAlloc function.
uBytes
Specifies the
new size, in bytes, of the memory block. If this parameter is zero and the uFlags
parameter specifies the LMEM_MOVEABLE flag, the function returns a handle to a
memory object that is marked as discarded. If uFlags specifies the
LMEM_MODIFY flag, this parameter is ignored.
uFlags
Specifies how
to reallocate the local memory object. If the LMEM_MODIFY flag is specified,
this parameter modifies the attributes of the memory object, and the uBytes
parameter is ignored. Otherwise, this parameter controls the reallocation of
the memory object.
The
LMEM_MODIFY flag can be combined with either or both of the following flags:
|
Flag |
Meaning |
|
LMEM_DISCARDABLE |
|
|
|
Allocates
discardable memory if the LMEM_MODIFY flag is also specified. This flag is
ignored, unless the object was previously allocated as movable or the
LMEM_MOVEABLE flag is also specified. |
|
LMEM_MOVEABLE |
|
|
|
You cannot
combine LMEM_MOVEABLE with LMEM_MODIFY to change a fixed memory object into a
movable one. The function returns an error if an application attempts this. |
If uFlags
does not specify LMEM_MODIFY, this parameter can be any combination of the following
flags:
|
Flag |
Meaning |
|
LMEM_MOVEABLE |
|
|
|
If uBytes
is zero, discards a previously movable and discardable memory block. If the
object s lock count is not zero or the block is not movable and discardable,
the function fails. |
|
|
If uBytes
is nonzero, enables the system to move the reallocated block to a new
location without changing the movable or fixed attribute of the memory
object. If the object is fixed, the handle returned may be different from the
handle specified in the hMem parameter. If the object is movable, the
block can be moved without invalidating the handle, even if the object is
currently locked by a previous call to the LocalLock function. To get the new
address of the memory block, use LocalLock. |
|
LMEM_NOCOMPACT |
|
|
|
Prevents
memory from being compacted or discarded to satisfy the allocation request. |
|
LMEM_ZEROINIT |
|
|
|
Causes the
additional memory contents to be initialized to zero if the memory object is
growing in size. |
Return Values
If the
function succeeds, the return value is the handle of the reallocated memory
object.
If the
function fails, the return value is NULL. To get extended error information,
call GetLastError.
Remarks
If LocalReAlloc
reallocates a movable object, the return value is the handle of the memory
object. To convert the handle to a pointer, use the LocalLock function.
If LocalReAlloc
reallocates a fixed object, the value of the handle returned is the address of
the first byte of the memory block. To access the memory, a process can simply
cast the return value to a pointer.
See Also