REALLOC(3) BSD Programmer's Manual REALLOC(3)
realloc - reallocation of memory function
realloc(void *ptr, size_t size);
The realloc() function changes the size of the object pointed to by ptr
to the size specified by size. The contents of the object are unchanged
up to the lesser of the new and old sizes. If the new size is larger,
the value of the newly allocated portion of the object is indeterminate.
If ptr is a null pointer, the realloc() function behaves like the mal-
loc(3) function for the specified size. Otherwise, if ptr does not match
a pointer earlier returned by the calloc(3), malloc(3), or realloc()
function, or if the space has been deallocated by a call to the free or
realloc() function, unpredictable and usually detrimental behavior will
occur. If the space cannot be allocated, the object pointed to by ptr is
unchanged. If size is zero and ptr is not a null pointer, the object it
points to is freed.
The realloc() function returns either a null pointer or a pointer to the
possibly moved allocated space.
alloca(3), calloc(3), free(3), malloc(3),
The realloc() function conforms to ANSI C X3.159-1989 (``ANSI C '').
4.4BSD April 19, 1994 1