| Platform SDK: Memory |
The LocalLock function locks a local memory object and returns a pointer to the first byte of the object's memory block.
Note The local functions are slower than other memory management functions and do not provide as many features. Therefore, new applications should use the heap functions.
LPVOID LocalLock( HLOCAL hMem // handle to local memory object );
If the function succeeds, the return value is a pointer to the first byte of the memory block.
If the function fails, the return value is NULL. To get extended error information, call GetLastError.
The internal data structures for each memory object include a lock count that is initially zero. For movable memory objects, LocalLock increments the count by one, and the LocalUnlock function decrements the count by one. For each call that a process makes to LocalLock for an object, it must eventually call LocalUnlock. Locked memory will not be moved or discarded unless the memory object is reallocated by using the LocalReAlloc function. The memory block of a locked memory object remains locked in memory until its lock count is decremented to zero, at which time it can be moved or discarded.
Memory objects allocated with LMEM_FIXED always have a lock count of zero. For these objects, the value of the returned pointer is equal to the value of the specified handle.
If the specified memory block has been discarded or if the memory block has a zero-byte size, this function returns NULL.
Discarded objects always have a lock count of zero.
Windows NT/2000: Requires Windows NT 3.1 or later.
Windows 95/98: Requires Windows 95 or later.
Header: Declared in Winbase.h; include Windows.h.
Library: Use Kernel32.lib.
Memory Management Overview, Memory Management Functions, LocalAlloc, LocalFlags, LocalReAlloc, LocalUnlock