hpux man page for xtrealloc

XtRealloc()															       XtRealloc()

Name
  XtRealloc - change the size of an allocated block of storage.

Synopsis
  char *XtRealloc(ptr, num);
	 char *ptr;
	 Cardinal num;

Inputs
  ptr	    Specifies a pointer to memory allocated with XtMalloc(), XtCalloc(), or XtRealloc(), or NULL.

  num	    Specifies the new number of bytes of memory desired in the block.

Returns
  A pointer to allocated memory.

Description
  XtRealloc() changes the size of the block of allocated memory pointed to by ptr to be at least num bytes large.  In order to make this size
  change, it may have to allocate a new block of memory and copy the contents of the old block (or as much as will fit) into the  new  block.
  If  it  allocates a new block of memory, it frees the old block.  In either case, it returns a pointer to a block of memory which is of the
  requested size.  If there is insufficient memory to allocate the new block, XtRealloc() terminates by calling XtErrorMsg().

  If ptr is NULL, XtRealloc() simply calls XtMalloc() to allocate a block of memory of the requested size.

Usage
  Note that XtRealloc() may move the contents of your allocated memory to a new location; the return value may or may not be the same as ptr.
  Not  all  memory can be safely reallocated.  If there are multiple pointers to a block of memory scattered through out an application (such
  as pointers to a widget record), then reallocating that memory is not safe, because all pointers to it cannot  be  updated.	Other  memory
  (such  as  the array of children maintained privately by the Composite widget class) can be safely updated because there should be only one
  pointer to it in the application (in this case the pointer is the composite.children field of the widget).  These cautions are no different
  than those required with the standard realloc() function.

  In most cases, you will have to cast the return value of XtRealloc() to an appropriate pointer type.

  Note that because XtRealloc() behaves like XtMalloc() when passed a NULL pointer, (something that realloc() does not do), you don't have to
  write special case code to allocate the first chunk of memory with XtMalloc() and subsequent chunks with XtRealloc(); you  can  simply  use
  XtRealloc() everywhere.

  Memory  allocated with XtRealloc() must be deallocated with XtFree().  The function XtRealloc() is implemented by the Toolkit independently
  of the particular environment, so programs ported to a system not supporting malloc will still work.

See Also
  XtCalloc(1), XtFree(1), XtMalloc(1), XtNew(1), XtNewString(1).

Xt - Memory Allocation														       XtRealloc()